diff --git a/examples/arrays.fun b/examples/arrays.fun
new file mode 100644
index 0000000..5986119
--- /dev/null
+++ b/examples/arrays.fun
@@ -0,0 +1,47 @@
+// Arrays basics
+arr = [1, 2, 3]
+print(arr)                 // -> [1, 2, 3]
+print(arr[0] + arr[1])     // -> 3
+
+// mutate last element
+arr[2] = arr[2] + 10
+print(arr)                 // -> [1, 2, 13]
+
+// Sum elements with while (fixed length)
+number i = 0
+number sum = 0
+number len = 3
+while i < len
+  sum = sum + arr[i]
+  i = i + 1
+print(sum)                 // -> 16
+
+// Fill with squares using for in range
+arr = [0, 0, 0, 0, 0]
+for i in range(0, 5)
+  arr[i] = i * i
+print(arr)                 // -> [0, 1, 4, 9, 16]
+
+// Nested arrays (matrix)
+matrix = [[1, 2], [3, 4], [5, 6]]
+print(matrix)              // -> [[1, 2], [3, 4], [5, 6]]
+print(matrix[1][0])        // -> 3
+
+// Function that mutates an array in place (first 3 elements)
+fun scale3(a, s)
+  number i = 0
+  while i < 3
+    a[i] = a[i] * s
+    i = i + 1
+
+arr = [2, 4, 6]
+scale3(arr, 5)
+print(arr)                 // -> [10, 20, 30]
+
+// Function that returns an array
+fun pair(x, y)
+  return [x, y]
+
+p = pair(7, 9)
+print(p)                   // -> [7, 9]
+print(p[1])                // -> 9
diff --git a/src/bytecode.c b/src/bytecode.c
index 062604b..6156c57 100644
--- a/src/bytecode.c
+++ b/src/bytecode.c
@@ -72,6 +72,9 @@ static const char *opcode_name(OpCode op) {
         case OP_NOT: return "NOT";
         case OP_DUP: return "DUP";
         case OP_SWAP: return "SWAP";
+        case OP_MAKE_ARRAY: return "MAKE_ARRAY";
+        case OP_INDEX_GET: return "INDEX_GET";
+        case OP_INDEX_SET: return "INDEX_SET";
         default: return "???";
     }
 }
diff --git a/src/bytecode.h b/src/bytecode.h
index 3e705cc..8424e3c 100644
--- a/src/bytecode.h
+++ b/src/bytecode.h
@@ -44,6 +44,11 @@ typedef enum {
 
     OP_DUP,          // duplicate top of stack
     OP_SWAP,         // swap top two stack values
+
+    // arrays
+    OP_MAKE_ARRAY,    // operand = element count; pops N values, pushes array
+    OP_INDEX_GET,     // pops index, array; pushes element copy
+    OP_INDEX_SET      // pops value, index, array; sets and pushes nothing
 } OpCode;
 
 typedef struct {
diff --git a/src/parser.c b/src/parser.c
index d1b4be0..4af4ff9 100644
--- a/src/parser.c
+++ b/src/parser.c
@@ -267,6 +267,18 @@ static int emit_primary(Bytecode *bc, const char *src, size_t len, size_t *pos)
             parser_fail(*pos, "Expected ')'");
             return 0;
         }
+        /* postfix indexing */
+        for (;;) {
+            skip_spaces(src, len, pos);
+            if (*pos < len && src[*pos] == '[') {
+                (*pos)++;
+                if (!emit_expression(bc, src, len, pos)) { parser_fail(*pos, "Expected index expression"); return 0; }
+                if (!consume_char(src, len, pos, ']')) { parser_fail(*pos, "Expected ']' after index"); return 0; }
+                bytecode_add_instruction(bc, OP_INDEX_GET, 0);
+                continue;
+            }
+            break;
+        }
         return 1;
     }
 
@@ -276,6 +288,56 @@ static int emit_primary(Bytecode *bc, const char *src, size_t len, size_t *pos)
         int ci = bytecode_add_constant(bc, make_string(s));
         free(s);
         bytecode_add_instruction(bc, OP_LOAD_CONST, ci);
+        /* postfix indexing */
+        for (;;) {
+            skip_spaces(src, len, pos);
+            if (*pos < len && src[*pos] == '[') {
+                (*pos)++;
+                if (!emit_expression(bc, src, len, pos)) { parser_fail(*pos, "Expected index expression"); return 0; }
+                if (!consume_char(src, len, pos, ']')) { parser_fail(*pos, "Expected ']' after index"); return 0; }
+                bytecode_add_instruction(bc, OP_INDEX_GET, 0);
+                continue;
+            }
+            break;
+        }
+        return 1;
+    }
+
+    /* array literal: [expr, expr, ...] */
+    skip_spaces(src, len, pos);
+    if (*pos < len && src[*pos] == '[') {
+        (*pos)++; /* '[' */
+        int count = 0;
+        skip_spaces(src, len, pos);
+        if (*pos < len && src[*pos] != ']') {
+            for (;;) {
+                if (!emit_expression(bc, src, len, pos)) {
+                    parser_fail(*pos, "Expected expression in array literal");
+                    return 0;
+                }
+                count++;
+                skip_spaces(src, len, pos);
+                if (*pos < len && src[*pos] == ',') { (*pos)++; skip_spaces(src, len, pos); continue; }
+                break;
+            }
+        }
+        if (!consume_char(src, len, pos, ']')) {
+            parser_fail(*pos, "Expected ']' to close array literal");
+            return 0;
+        }
+        bytecode_add_instruction(bc, OP_MAKE_ARRAY, count);
+        /* postfix indexing */
+        for (;;) {
+            skip_spaces(src, len, pos);
+            if (*pos < len && src[*pos] == '[') {
+                (*pos)++;
+                if (!emit_expression(bc, src, len, pos)) { parser_fail(*pos, "Expected index expression"); return 0; }
+                if (!consume_char(src, len, pos, ']')) { parser_fail(*pos, "Expected ']' after index"); return 0; }
+                bytecode_add_instruction(bc, OP_INDEX_GET, 0);
+                continue;
+            }
+            break;
+        }
         return 1;
     }
 
@@ -286,6 +348,18 @@ static int emit_primary(Bytecode *bc, const char *src, size_t len, size_t *pos)
     if (ok) {
         int ci = bytecode_add_constant(bc, make_int(ival));
         bytecode_add_instruction(bc, OP_LOAD_CONST, ci);
+        /* postfix indexing */
+        for (;;) {
+            skip_spaces(src, len, pos);
+            if (*pos < len && src[*pos] == '[') {
+                (*pos)++;
+                if (!emit_expression(bc, src, len, pos)) { parser_fail(*pos, "Expected index expression"); return 0; }
+                if (!consume_char(src, len, pos, ']')) { parser_fail(*pos, "Expected ']' after index"); return 0; }
+                bytecode_add_instruction(bc, OP_INDEX_GET, 0);
+                continue;
+            }
+            break;
+        }
         return 1;
     }
     *pos = save;
@@ -338,6 +412,18 @@ static int emit_primary(Bytecode *bc, const char *src, size_t len, size_t *pos)
             printf("compile: CALL %s with %d arg(s)\n", name, argc);
 #endif
             bytecode_add_instruction(bc, OP_CALL, argc);
+            /* postfix indexing */
+            for (;;) {
+                skip_spaces(src, len, pos);
+                if (*pos < len && src[*pos] == '[') {
+                    (*pos)++;
+                    if (!emit_expression(bc, src, len, pos)) { parser_fail(*pos, "Expected index expression"); free(name); return 0; }
+                    if (!consume_char(src, len, pos, ']')) { parser_fail(*pos, "Expected ']' after index"); free(name); return 0; }
+                    bytecode_add_instruction(bc, OP_INDEX_GET, 0);
+                    continue;
+                }
+                break;
+            }
             free(name);
             return 1;
         } else {
@@ -347,6 +433,18 @@ static int emit_primary(Bytecode *bc, const char *src, size_t len, size_t *pos)
                 int gi = sym_index(name);
                 bytecode_add_instruction(bc, OP_LOAD_GLOBAL, gi);
             }
+            /* postfix indexing */
+            for (;;) {
+                skip_spaces(src, len, pos);
+                if (*pos < len && src[*pos] == '[') {
+                    (*pos)++;
+                    if (!emit_expression(bc, src, len, pos)) { parser_fail(*pos, "Expected index expression"); free(name); return 0; }
+                    if (!consume_char(src, len, pos, ']')) { parser_fail(*pos, "Expected ']' after index"); free(name); return 0; }
+                    bytecode_add_instruction(bc, OP_INDEX_GET, 0);
+                    continue;
+                }
+                break;
+            }
             free(name);
             return 1;
         }
@@ -798,8 +896,48 @@ static void parse_simple_statement(Bytecode *bc, const char *src, size_t len, si
         /* assignment or simple call */
         int lidx = local_find(name);
         int gi = (lidx < 0) ? sym_index(name) : -1;
-        free(name);
         skip_spaces(src, len, &local_pos);
+
+        /* array element assignment: name[expr] = expr */
+        if (local_pos < len && src[local_pos] == '[') {
+            /* load array variable */
+            if (lidx >= 0) {
+                bytecode_add_instruction(bc, OP_LOAD_LOCAL, lidx);
+            } else {
+                bytecode_add_instruction(bc, OP_LOAD_GLOBAL, gi);
+            }
+            local_pos++; /* '[' */
+            if (!emit_expression(bc, src, len, &local_pos)) {
+                parser_fail(local_pos, "Expected index expression after '['");
+                free(name);
+                return;
+            }
+            if (!consume_char(src, len, &local_pos, ']')) {
+                parser_fail(local_pos, "Expected ']' after index");
+                free(name);
+                return;
+            }
+            skip_spaces(src, len, &local_pos);
+            if (local_pos >= len || src[local_pos] != '=') {
+                parser_fail(local_pos, "Expected '=' after array index");
+                free(name);
+                return;
+            }
+            local_pos++; /* '=' */
+            if (!emit_expression(bc, src, len, &local_pos)) {
+                parser_fail(local_pos, "Expected expression after '='");
+                free(name);
+                return;
+            }
+            /* perform set */
+            bytecode_add_instruction(bc, OP_INDEX_SET, 0);
+            free(name);
+            *pos = local_pos;
+            skip_to_eol(src, len, pos);
+            return;
+        }
+
+        free(name);
         if (local_pos < len && src[local_pos] == '=') {
             local_pos++; /* '=' */
             if (emit_expression(bc, src, len, &local_pos)) {
diff --git a/src/value.c b/src/value.c
index f1d03cb..b0a0b5a 100644
--- a/src/value.c
+++ b/src/value.c
@@ -3,6 +3,12 @@
 #include <string.h>
 #include <stdio.h>
 
+typedef struct Array {
+    int refcount;
+    int count;
+    Value *items; /* owns items; each item owned by array */
+} Array;
+
 Value make_int(int64_t v) {
     Value val;
     val.type = VAL_INT;
@@ -31,6 +37,58 @@ Value make_nil(void) {
     return v;
 }
 
+Value make_array_from_values(const Value *vals, int count) {
+    if (count < 0) count = 0;
+    Array *arr = (Array*)malloc(sizeof(Array));
+    if (!arr) {
+        Value nil = make_nil();
+        return nil;
+    }
+    arr->refcount = 1;
+    arr->count = count;
+    if (count > 0) {
+        arr->items = (Value*)malloc(sizeof(Value) * count);
+        if (!arr->items) {
+            free(arr);
+            Value nil = make_nil();
+            return nil;
+        }
+        for (int i = 0; i < count; ++i) {
+            arr->items[i] = copy_value(&vals[i]);
+        }
+    } else {
+        arr->items = NULL;
+    }
+    Value v;
+    v.type = VAL_ARRAY;
+    v.arr = (struct Array*)arr;
+    return v;
+}
+
+int array_length(const Value *v) {
+    if (!v || v->type != VAL_ARRAY || !v->arr) return -1;
+    const Array *a = (const Array*)v->arr;
+    return a->count;
+}
+
+int array_get_copy(const Value *v, int index, Value *out) {
+    if (!v || v->type != VAL_ARRAY || !v->arr) return 0;
+    const Array *a = (const Array*)v->arr;
+    if (index < 0 || index >= a->count) return 0;
+    if (out) *out = copy_value(&a->items[index]);
+    return 1;
+}
+
+int array_set(Value *v, int index, Value newElem) {
+    if (!v || v->type != VAL_ARRAY || !v->arr) return 0;
+    Array *a = (Array*)v->arr;
+    if (index < 0 || index >= a->count) return 0;
+    /* replace element: free old, take ownership of newElem */
+    free_value(a->items[index]);
+    a->items[index] = newElem;
+    return 1;
+}
+
 Value copy_value(const Value *v) {
     Value out;
     out.type = v->type;
@@ -44,6 +102,12 @@ Value copy_value(const Value *v) {
         case VAL_FUNCTION:
             out.fn = v->fn; /* shallow copy pointer */
             break;
+        case VAL_ARRAY: {
+            Array *a = (Array*)v->arr;
+            out.arr = (struct Array*)a;
+            if (a) a->refcount++;
+            break;
+        }
         case VAL_NIL:
         default:
             break;
@@ -54,6 +118,15 @@ Value copy_value(const Value *v) {
 void free_value(Value v) {
     if (v.type == VAL_STRING && v.s) {
         free(v.s);
+    } else if (v.type == VAL_ARRAY && v.arr) {
+        Array *a = (Array*)v.arr;
+        if (--a->refcount == 0) {
+            for (int i = 0; i < a->count; ++i) {
+                free_value(a->items[i]);
+            }
+            free(a->items);
+            free(a);
+        }
     }
     /* VAL_FUNCTION: we *do not* free the Bytecode here (caller frees it) */
 }
@@ -69,6 +142,18 @@ void print_value(const Value *v) {
         case VAL_FUNCTION:
             printf("<function@%p>", (void*)v->fn);
             break;
+        case VAL_ARRAY: {
+            const Array *a = (const Array*)v->arr;
+            printf("[");
+            if (a) {
+                for (int i = 0; i < a->count; ++i) {
+                    if (i > 0) printf(", ");
+                    print_value(&a->items[i]);
+                }
+            }
+            printf("]");
+            break;
+        }
         case VAL_NIL:
         default:
             printf("nil");
@@ -84,6 +169,10 @@ int value_is_truthy(const Value *v) {
             return v->s && v->s[0] != '\0';
         case VAL_FUNCTION:
             return 1;
+        case VAL_ARRAY: {
+            const Array *a = (const Array*)v->arr;
+            return a && a->count > 0;
+        }
         case VAL_NIL:
         default:
             return 0;
@@ -106,6 +195,12 @@ char *value_to_string_alloc(const Value *v) {
             snprintf(buf, sizeof(buf), "<function@%p>", (void*)v->fn);
             return strdup(buf);
         }
+        case VAL_ARRAY: {
+            int n = array_length(v);
+            if (n < 0) n = 0;
+            snprintf(buf, sizeof(buf), "[array n=%d]", n);
+            return strdup(buf);
+        }
         case VAL_NIL:
         default:
             return strdup("nil");
diff --git a/src/value.h b/src/value.h
index 70fb955..eefb878 100644
--- a/src/value.h
+++ b/src/value.h
@@ -4,11 +4,13 @@
 #include <inttypes.h>
 
 struct Bytecode; /* forward */
+struct Array;    /* forward */
 
 typedef enum {
     VAL_INT,
     VAL_STRING,
     VAL_FUNCTION,
+    VAL_ARRAY,
     VAL_NIL
 } ValueType;
 
@@ -18,6 +20,7 @@ typedef struct {
         int64_t i;
         char *s;
         struct Bytecode *fn;
+        struct Array *arr;
     };
 } Value;
 
@@ -27,9 +30,15 @@ Value make_string(const char *s);
 Value make_function(struct Bytecode *fn);
 Value make_nil(void);
 
-/* copy (deep for strings), free (free string only) */
-Value copy_value(const Value *v);
-void free_value(Value v);
+/* arrays */
+Value make_array_from_values(const Value *vals, int count); /* deep-copies vals */
+int array_length(const Value *v);                            /* returns -1 if not array */
+int array_get_copy(const Value *v, int index, Value *out);   /* returns 0 on error; out = copy_value(item) */
+int array_set(Value *v, int index, Value newElem);           /* returns 0 on error; takes ownership of newElem */
+
+/* copy/free */
+Value copy_value(const Value *v);    /* deep for strings, RC for arrays, shallow fn */
+void free_value(Value v);            /* frees owned resources */
 
 /* utilities */
 void print_value(const Value *v);
diff --git a/src/vm.c b/src/vm.c
index 0cc98d0..c48b0ad 100644
--- a/src/vm.c
+++ b/src/vm.c
@@ -485,6 +485,72 @@ void vm_run(VM *vm, Bytecode *entry) {
                 break;
             }
 
+            case OP_MAKE_ARRAY: {
+                int n = inst.operand;
+                if (n < 0 || vm->sp + 1 < n) {
+                    fprintf(stderr, "Runtime error: invalid element count for MAKE_ARRAY\n");
+                    exit(1);
+                }
+                /* pop n values into temp array preserving original order */
+                Value *vals = (Value*)malloc(sizeof(Value) * n);
+                if (!vals) { fprintf(stderr, "Runtime error: OOM in MAKE_ARRAY\n"); exit(1); }
+                for (int i = n - 1; i >= 0; --i) {
+                    vals[i] = pop_value(vm); /* take ownership */
+                }
+                /* build array by copying values, then free originals */
+                Value arr = make_array_from_values(vals, n);
+                for (int i = 0; i < n; ++i) {
+                    free_value(vals[i]);
+                }
+                free(vals);
+                push_value(vm, arr);
+                break;
+            }
+
+            case OP_INDEX_GET: {
+                Value idx = pop_value(vm);
+                Value arr = pop_value(vm);
+                if (arr.type != VAL_ARRAY) {
+                    fprintf(stderr, "Runtime type error: INDEX_GET expects array\n");
+                    exit(1);
+                }
+                if (idx.type != VAL_INT) {
+                    fprintf(stderr, "Runtime type error: INDEX_GET index must be int\n");
+                    exit(1);
+                }
+                Value elem;
+                if (!array_get_copy(&arr, (int)idx.i, &elem)) {
+                    fprintf(stderr, "Runtime error: index out of range\n");
+                    exit(1);
+                }
+                free_value(arr);
+                free_value(idx);
+                push_value(vm, elem);
+                break;
+            }
+
+            case OP_INDEX_SET: {
+                Value v = pop_value(vm);
+                Value idx = pop_value(vm);
+                Value arr = pop_value(vm);
+                if (arr.type != VAL_ARRAY) {
+                    fprintf(stderr, "Runtime type error: INDEX_SET expects array\n");
+                    exit(1);
+                }
+                if (idx.type != VAL_INT) {
+                    fprintf(stderr, "Runtime type error: INDEX_SET index must be int\n");
+                    exit(1);
+                }
+                if (!array_set(&arr, (int)idx.i, v)) {
+                    fprintf(stderr, "Runtime error: index out of range\n");
+                    exit(1);
+                }
+                /* arr modified in place; do not free v (ownership moved) */
+                free_value(arr);
+                free_value(idx);
+                break;
+            }
+
             case OP_LOAD_GLOBAL: {
                 int idx = inst.operand;
                 if (idx < 0 || idx >= VM_MAX_GLOBALS) {
diff --git a/src/vm.h b/src/vm.h
index c5e34b6..921f44f 100644
--- a/src/vm.h
+++ b/src/vm.h
@@ -14,7 +14,8 @@ static const char *opcode_names[] = {
     "LOAD_GLOBAL","STORE_GLOBAL","ADD","SUB","MUL","DIV",
     "LT","LTE","GT","GTE","EQ","NEQ","POP","JUMP",
     "JUMP_IF_FALSE","CALL","RETURN","PRINT","HALT",
-    "MOD","AND","OR","NOT","DUP","SWAP"
+    "MOD","AND","OR","NOT","DUP","SWAP",
+    "MAKE_ARRAY","INDEX_GET","INDEX_SET"
 };
 
 typedef struct {
@@ -55,7 +56,7 @@ void vm_dump_globals(VM *vm);
 void vm_run(VM *vm, Bytecode *entry);
 
 static inline int opcode_is_valid(int op) {
-    return op >= OP_NOP && op <= OP_SWAP;  // all current opcodes
+    return op >= OP_NOP && op <= OP_INDEX_SET;  // all current opcodes
 }
 
 #endif