diff --git a/CMakeLists.txt b/CMakeLists.txt
index 6947a82..2af9cbf 100644
--- a/CMakeLists.txt
+++ b/CMakeLists.txt
@@ -1,5 +1,5 @@
 cmake_minimum_required(VERSION 3.16)
-project(fun VERSION 0.19.0 LANGUAGES C)
+project(fun VERSION 0.20.0 LANGUAGES C)
 
 set(CMAKE_C_STANDARD 11)
 set(CMAKE_C_STANDARD_REQUIRED ON)
diff --git a/examples/regex_demo.fun b/examples/regex_demo.fun
new file mode 100644
index 0000000..8ea3637
--- /dev/null
+++ b/examples/regex_demo.fun
@@ -0,0 +1,38 @@
+#!/usr/bin/env fun
+
+/*
+ * This file is part of the Fun programming language.
+ * https://hanez.org/project/fun/
+ *
+ * Copyright 2025 Johannes Findeisen <you@hanez.org>
+ * Licensed under the terms of the Apache-2.0 license.
+ * https://opensource.org/license/apache-2-0
+ *
+ * Added: 2025-10-04
+ */
+
+// Simple demo of Regex stdlib class.
+
+include <regex.fun>
+
+r = Regex()
+
+text = "abc-123-xyz"
+
+// full match (should be 0)
+m1 = r.match(text, "[a-z]+-[0-9]+-[a-z]+$")
+print(m1)
+
+// search
+s1 = r.search(text, "[0-9]+")
+print(s1)
+
+// replace digits with #
+out = r.replace(text, "[0-9]", "#")
+print(out)
+
+/* Expected output:
+1
+{"match": 123, "start": 4, "end": 7, "groups": []}
+abc-###-xyz
+*/
diff --git a/examples/regex_procedural.fun b/examples/regex_procedural.fun
new file mode 100644
index 0000000..7036ceb
--- /dev/null
+++ b/examples/regex_procedural.fun
@@ -0,0 +1,35 @@
+#!/usr/bin/env fun
+
+/*
+ * This file is part of the Fun programming language.
+ * https://hanez.org/project/fun/
+ *
+ * Copyright 2025 Johannes Findeisen <you@hanez.org>
+ * Licensed under the terms of the Apache-2.0 license.
+ * https://opensource.org/license/apache-2-0
+ *
+ * Added: 2025-10-04
+ */
+
+// Procedural regex demo using built-in functions.
+// Shows internal power without the Regex class wrapper.
+
+text = "abc-123-xyz"
+
+// Full string match
+m1 = regex_match(text, "[a-z]+-[0-9]+-[a-z]+$")
+print(m1)
+
+// First search with groups (prints a map)
+s1 = regex_search(text, "([0-9])([0-9])([0-9])")
+print(s1)
+
+// Global replace: replace digits with '#'
+out = regex_replace(text, "[0-9]", "#")
+print(out)
+
+/* Expected output:
+1
+{"match": 123, "start": 4, "end": 7, "groups": [1, 2, 3]}
+abc-###-xyz
+*/
diff --git a/lib/regex.fun b/lib/regex.fun
new file mode 100644
index 0000000..fbe0213
--- /dev/null
+++ b/lib/regex.fun
@@ -0,0 +1,33 @@
+/*
+ * This file is part of the Fun programming language.
+ * https://hanez.org/project/fun/
+ *
+ * Copyright 2025 Johannes Findeisen <you@hanez.org>
+ * Licensed under the terms of the Apache-2.0 license.
+ * https://opensource.org/license/apache-2-0
+ *
+ * Added: 2025-10-04
+ */
+
+// Regex stdlib abstraction over VM regex opcodes.
+// Provides simple methods and sensible defaults.
+
+/*
+Methods:
+- match(text, pattern) -> 1/0 (full match)
+- search(text, pattern) -> map {"match": str, "start": int, "end": int, "groups": array}
+- replace(text, pattern, repl) -> string (global)
+*/
+
+class Regex()
+  // Full match: returns 1 if the whole string matches the pattern
+  fun match(this, text, pattern)
+    return regex_match(to_string(text), to_string(pattern))
+
+  // First match with groups as array
+  fun search(this, text, pattern)
+    return regex_search(to_string(text), to_string(pattern))
+
+  // Global replace; replacement is literal (no backrefs)
+  fun replace(this, text, pattern, repl)
+    return regex_replace(to_string(text), to_string(pattern), to_string(repl))
diff --git a/src/bytecode.c b/src/bytecode.c
index 901c67f..6fa5091 100644
--- a/src/bytecode.c
+++ b/src/bytecode.c
@@ -98,6 +98,9 @@ static const char *opcode_name(OpCode op) {
         case OP_JOIN: return "JOIN";
         case OP_SUBSTR: return "SUBSTR";
         case OP_FIND: return "FIND";
+        case OP_REGEX_MATCH: return "REGEX_MATCH";
+        case OP_REGEX_SEARCH: return "REGEX_SEARCH";
+        case OP_REGEX_REPLACE: return "REGEX_REPLACE";
         case OP_CONTAINS: return "CONTAINS";
         case OP_INDEX_OF: return "INDEX_OF";
         case OP_CLEAR: return "CLEAR";
diff --git a/src/bytecode.h b/src/bytecode.h
index 082cdb5..63a6059 100644
--- a/src/bytecode.h
+++ b/src/bytecode.h
@@ -84,6 +84,11 @@ typedef enum {
     OP_SUBSTR,        // pops len, start, string; pushes string
     OP_FIND,          // pops needle, haystack; pushes int index or -1
 
+    // regex ops (POSIX)
+    OP_REGEX_MATCH,   // pops pattern, string; pushes 1/0 for full match
+    OP_REGEX_SEARCH,  // pops pattern, string; pushes map {"match":str, "start":int, "end":int, "groups":array}
+    OP_REGEX_REPLACE, // pops repl, pattern, string; pushes string with global replacements
+
     // array utils
     OP_CONTAINS,      // pops value, array; pushes 1/0
     OP_INDEX_OF,      // pops value, array; pushes index or -1
diff --git a/src/parser.c b/src/parser.c
index 0f65f01..cb8e537 100644
--- a/src/parser.c
+++ b/src/parser.c
@@ -800,6 +800,39 @@ static int emit_primary(Bytecode *bc, const char *src, size_t len, size_t *pos)
                 free(name);
                 return 1;
             }
+            /* regex ops */
+            if (strcmp(name, "regex_match") == 0) {
+                (*pos)++; /* '(' */
+                if (!emit_expression(bc, src, len, pos)) { parser_fail(*pos, "regex_match expects text"); free(name); return 0; }
+                if (*pos < len && src[*pos] == ',') { (*pos)++; skip_spaces(src, len, pos); } else { parser_fail(*pos, "regex_match expects 2 args"); free(name); return 0; }
+                if (!emit_expression(bc, src, len, pos)) { parser_fail(*pos, "regex_match expects pattern"); free(name); return 0; }
+                if (!consume_char(src, len, pos, ')')) { parser_fail(*pos, "Expected ')' after regex_match args"); free(name); return 0; }
+                bytecode_add_instruction(bc, OP_REGEX_MATCH, 0);
+                free(name);
+                return 1;
+            }
+            if (strcmp(name, "regex_search") == 0) {
+                (*pos)++; /* '(' */
+                if (!emit_expression(bc, src, len, pos)) { parser_fail(*pos, "regex_search expects text"); free(name); return 0; }
+                if (*pos < len && src[*pos] == ',') { (*pos)++; skip_spaces(src, len, pos); } else { parser_fail(*pos, "regex_search expects 2 args"); free(name); return 0; }
+                if (!emit_expression(bc, src, len, pos)) { parser_fail(*pos, "regex_search expects pattern"); free(name); return 0; }
+                if (!consume_char(src, len, pos, ')')) { parser_fail(*pos, "Expected ')' after regex_search args"); free(name); return 0; }
+                bytecode_add_instruction(bc, OP_REGEX_SEARCH, 0);
+                free(name);
+                return 1;
+            }
+            if (strcmp(name, "regex_replace") == 0) {
+                (*pos)++; /* '(' */
+                if (!emit_expression(bc, src, len, pos)) { parser_fail(*pos, "regex_replace expects text"); free(name); return 0; }
+                if (*pos < len && src[*pos] == ',') { (*pos)++; skip_spaces(src, len, pos); } else { parser_fail(*pos, "regex_replace expects 3 args"); free(name); return 0; }
+                if (!emit_expression(bc, src, len, pos)) { parser_fail(*pos, "regex_replace expects pattern"); free(name); return 0; }
+                if (*pos < len && src[*pos] == ',') { (*pos)++; skip_spaces(src, len, pos); } else { parser_fail(*pos, "regex_replace expects 3 args"); free(name); return 0; }
+                if (!emit_expression(bc, src, len, pos)) { parser_fail(*pos, "regex_replace expects replacement"); free(name); return 0; }
+                if (!consume_char(src, len, pos, ')')) { parser_fail(*pos, "Expected ')' after regex_replace args"); free(name); return 0; }
+                bytecode_add_instruction(bc, OP_REGEX_REPLACE, 0);
+                free(name);
+                return 1;
+            }
             /* array utils */
             if (strcmp(name, "contains") == 0) {
                 (*pos)++; /* '(' */
diff --git a/src/vm.c b/src/vm.c
index 9e06dbe..11495a8 100644
--- a/src/vm.c
+++ b/src/vm.c
@@ -338,6 +338,9 @@ void vm_run(VM *vm, Bytecode *entry) {
             #include "vm/pcsc/transmit.c"
 
             #include "vm/strings/find.c"
+            #include "vm/strings/regex_match.c"
+            #include "vm/strings/regex_search.c"
+            #include "vm/strings/regex_replace.c"
             #include "vm/strings/split.c"
             #include "vm/strings/substr.c"
 
diff --git a/src/vm.h b/src/vm.h
index 7028060..246f158 100644
--- a/src/vm.h
+++ b/src/vm.h
@@ -29,6 +29,7 @@ static const char *opcode_names[] = {
     "LEN","PUSH","APOP","SET","INSERT","REMOVE","SLICE",
     "TO_NUMBER","TO_STRING","CAST","TYPEOF",
     "SPLIT","JOIN","SUBSTR","FIND",
+    "REGEX_MATCH","REGEX_SEARCH","REGEX_REPLACE",
     "CONTAINS","INDEX_OF","CLEAR",
     "ENUMERATE","ZIP",
     "MIN","MAX","CLAMP","ABS","POW","RANDOM_SEED","RANDOM_INT",
diff --git a/src/vm/strings/regex_match.c b/src/vm/strings/regex_match.c
new file mode 100644
index 0000000..43ceacb
--- /dev/null
+++ b/src/vm/strings/regex_match.c
@@ -0,0 +1,57 @@
+/**
+ * This file is part of the Fun programming language.
+ * https://hanez.org/project/fun/
+ *
+ * Copyright 2025 Johannes Findeisen <you@hanez.org>
+ * Licensed under the terms of the Apache-2.0 license.
+ * https://opensource.org/license/apache-2-0
+ *
+ * Added: 2025-10-04
+ */
+
+/* Regex full-match opcode using POSIX regex */
+#ifdef __unix__
+#include <regex.h>
+#endif
+
+case OP_REGEX_MATCH: {
+    Value pattern = pop_value(vm);
+    Value str = pop_value(vm);
+    if (str.type != VAL_STRING || pattern.type != VAL_STRING) {
+        fprintf(stderr, "Runtime type error: REGEX_MATCH expects (string, string)\n");
+        exit(1);
+    }
+#ifndef __unix__
+    /* Not supported on non-UNIX: return 0 gracefully */
+    free_value(pattern);
+    int truth = 0;
+    free_value(str);
+    push_value(vm, make_int(truth));
+    break;
+#else
+    regex_t rx;
+    int rc = regcomp(&rx, pattern.s ? pattern.s : "", REG_EXTENDED);
+    if (rc != 0) {
+        /* invalid regex -> false */
+        free_value(pattern);
+        free_value(str);
+        push_value(vm, make_int(0));
+        break;
+    }
+    regmatch_t m;
+    int ok = regexec(&rx, str.s ? str.s : "", 1, &m, 0) == 0;
+    int truth = 0;
+    if (ok) {
+        /* full match means the match spans whole string */
+        if (m.rm_so == 0 && str.s) {
+            size_t slen = strlen(str.s);
+            truth = (m.rm_eo == (regoff_t)slen) ? 1 : 0;
+        }
+    }
+    regfree(&rx);
+    free_value(pattern);
+    free_value(str);
+    push_value(vm, make_int(truth));
+    break;
+#endif
+}
diff --git a/src/vm/strings/regex_replace.c b/src/vm/strings/regex_replace.c
new file mode 100644
index 0000000..3d29c95
--- /dev/null
+++ b/src/vm/strings/regex_replace.c
@@ -0,0 +1,116 @@
+/**
+ * This file is part of the Fun programming language.
+ * https://hanez.org/project/fun/
+ *
+ * Copyright 2025 Johannes Findeisen <you@hanez.org>
+ * Licensed under the terms of the Apache-2.0 license.
+ * https://opensource.org/license/apache-2-0
+ *
+ * Added: 2025-10-04
+ */
+
+/* Regex global replace opcode using POSIX regex */
+#ifdef __unix__
+#include <regex.h>
+#include <string.h>
+#include <stdlib.h>
+#endif
+
+case OP_REGEX_REPLACE: {
+    Value repl = pop_value(vm);
+    Value pattern = pop_value(vm);
+    Value str = pop_value(vm);
+    if (str.type != VAL_STRING || pattern.type != VAL_STRING || repl.type != VAL_STRING) {
+        fprintf(stderr, "Runtime type error: REGEX_REPLACE expects (string, string, string)\n");
+        exit(1);
+    }
+#ifndef __unix__
+    /* Not supported: return original string */
+    Value out = make_string(str.s ? str.s : "");
+    free_value(repl);
+    free_value(pattern);
+    free_value(str);
+    push_value(vm, out);
+    break;
+#else
+    regex_t rx;
+    int rc = regcomp(&rx, pattern.s ? pattern.s : "", REG_EXTENDED);
+    if (rc != 0) {
+        /* invalid regex -> return original */
+        Value out = make_string(str.s ? str.s : "");
+        free_value(repl);
+        free_value(pattern);
+        free_value(str);
+        push_value(vm, out);
+        break;
+    }
+
+    const char *s = str.s ? str.s : "";
+    const char *r = repl.s ? repl.s : "";
+
+    size_t out_cap = strlen(s) + 1;
+    char *outbuf = (char*)malloc(out_cap);
+    size_t out_len = 0;
+    size_t pos = 0;
+
+    enum { MAX_CAP = 16 };
+    regmatch_t caps[MAX_CAP];
+
+    while (1) {
+        if (regexec(&rx, s + pos, MAX_CAP, caps, 0) != 0) {
+            /* no more matches: append the rest */
+            size_t rest = strlen(s + pos);
+            if (out_len + rest + 1 > out_cap) {
+                out_cap = out_len + rest + 1;
+                outbuf = (char*)realloc(outbuf, out_cap);
+            }
+            memcpy(outbuf + out_len, s + pos, rest + 1);
+            out_len += rest;
+            break;
+        }
+        int mstart = (int)caps[0].rm_so;
+        int mend   = (int)caps[0].rm_eo;
+        if (mstart < 0 || mend < mstart) {
+            /* Shouldn't happen, avoid infinite loop */
+            break;
+        }
+        /* append prefix */
+        size_t pre_len = (size_t)mstart;
+        if (out_len + pre_len + 1 > out_cap) {
+            out_cap = (out_len + pre_len + 1) * 2;
+            outbuf = (char*)realloc(outbuf, out_cap);
+        }
+        memcpy(outbuf + out_len, s + pos, pre_len);
+        out_len += pre_len;
+
+        /* append replacement (no backref expansion for simplicity) */
+        size_t rlen = strlen(r);
+        if (out_len + rlen + 1 > out_cap) {
+            out_cap = (out_len + rlen + 1) * 2;
+            outbuf = (char*)realloc(outbuf, out_cap);
+        }
+        memcpy(outbuf + out_len, r, rlen);
+        out_len += rlen;
+
+        /* advance */
+        pos += (size_t)mend;
+        if (mend == 0) { /* prevent zero-length match infinite loop */
+            if (pos < strlen(s)) {
+                if (out_len + 1 > out_cap) { out_cap = out_len + 2; outbuf = (char*)realloc(outbuf, out_cap);}                
+                outbuf[out_len++] = s[pos++];
+            } else {
+                break;
+            }
+        }
+    }
+
+    Value out = make_string(outbuf ? outbuf : "");
+    if (outbuf) free(outbuf);
+    regfree(&rx);
+    free_value(repl);
+    free_value(pattern);
+    free_value(str);
+    push_value(vm, out);
+    break;
+#endif
+}
diff --git a/src/vm/strings/regex_search.c b/src/vm/strings/regex_search.c
new file mode 100644
index 0000000..1baf602
--- /dev/null
+++ b/src/vm/strings/regex_search.c
@@ -0,0 +1,113 @@
+/**
+ * This file is part of the Fun programming language.
+ * https://hanez.org/project/fun/
+ *
+ * Copyright 2025 Johannes Findeisen <you@hanez.org>
+ * Licensed under the terms of the Apache-2.0 license.
+ * https://opensource.org/license/apache-2-0
+ *
+ * Added: 2025-10-04
+ */
+
+/* Regex search (first match) opcode using POSIX regex */
+#ifdef __unix__
+#include <regex.h>
+#include <string.h>
+#include <stdlib.h>
+#endif
+
+case OP_REGEX_SEARCH: {
+    Value pattern = pop_value(vm);
+    Value str = pop_value(vm);
+    if (str.type != VAL_STRING || pattern.type != VAL_STRING) {
+        fprintf(stderr, "Runtime type error: REGEX_SEARCH expects (string, string)\n");
+        exit(1);
+    }
+#ifndef __unix__
+    /* Return default empty result on unsupported platforms */
+    Value m = make_map_empty();
+    (void)map_set(&m, "match", make_string(""));
+    (void)map_set(&m, "start", make_int(-1));
+    (void)map_set(&m, "end", make_int(-1));
+    Value emptyArr = make_array_from_values(NULL, 0);
+    (void)map_set(&m, "groups", emptyArr);
+    free_value(pattern);
+    free_value(str);
+    push_value(vm, m);
+    break;
+#else
+    regex_t rx;
+    int rc = regcomp(&rx, pattern.s ? pattern.s : "", REG_EXTENDED);
+    if (rc != 0) {
+        /* invalid regex -> empty result */
+        Value m = make_map_empty();
+        (void)map_set(&m, "match", make_string(""));
+        (void)map_set(&m, "start", make_int(-1));
+        (void)map_set(&m, "end", make_int(-1));
+        Value emptyArr = make_array_from_values(NULL, 0);
+        (void)map_set(&m, "groups", emptyArr);
+        free_value(pattern);
+        free_value(str);
+        push_value(vm, m);
+        break;
+    }
+    /* capture up to, say, 10 groups (including whole match) */
+    enum { MAX_CAP = 16 };
+    regmatch_t caps[MAX_CAP];
+    int ok = regexec(&rx, str.s ? str.s : "", MAX_CAP, caps, 0) == 0;
+    Value outMap = make_map_empty();
+    if (!ok) {
+        (void)map_set(&outMap, "match", make_string(""));
+        (void)map_set(&outMap, "start", make_int(-1));
+        (void)map_set(&outMap, "end", make_int(-1));
+        Value emptyArr = make_array_from_values(NULL, 0);
+        (void)map_set(&outMap, "groups", emptyArr);
+    } else {
+        int s = (int)caps[0].rm_so;
+        int e = (int)caps[0].rm_eo;
+        char *matchStr = NULL;
+        if (str.s && s >= 0 && e >= s) {
+            int len = e - s;
+            matchStr = (char*)malloc((size_t)len + 1);
+            if (matchStr) { memcpy(matchStr, str.s + s, (size_t)len); matchStr[len] = '\0'; }
+        }
+        (void)map_set(&outMap, "match", make_string(matchStr ? matchStr : ""));
+        if (matchStr) free(matchStr);
+        (void)map_set(&outMap, "start", make_int(s));
+        (void)map_set(&outMap, "end", make_int(e));
+        /* groups 1..n */
+        Value groupsArr = make_array_from_values(NULL, 0);
+        /* Count groups available */
+        int groupCount = 0;
+        for (int i = 1; i < MAX_CAP; ++i) {
+            if (caps[i].rm_so == -1 || caps[i].rm_eo == -1) break;
+            groupCount++;
+        }
+        if (groupCount > 0) {
+            Value *vals = (Value*)calloc((size_t)groupCount, sizeof(Value));
+            int vi = 0;
+            for (int i = 1; i <= groupCount; ++i) {
+                int gs = (int)caps[i].rm_so;
+                int ge = (int)caps[i].rm_eo;
+                char *gstr = NULL;
+                if (str.s && gs >= 0 && ge >= gs) {
+                    int gl = ge - gs;
+                    gstr = (char*)malloc((size_t)gl + 1);
+                    if (gstr) { memcpy(gstr, str.s + gs, (size_t)gl); gstr[gl] = '\0'; }
+                }
+                vals[vi++] = make_string(gstr ? gstr : "");
+                if (gstr) free(gstr);
+            }
+            groupsArr = make_array_from_values(vals, groupCount);
+            for (int i = 0; i < groupCount; ++i) free_value(vals[i]);
+            free(vals);
+        }
+        (void)map_set(&outMap, "groups", groupsArr);
+    }
+    regfree(&rx);
+    free_value(pattern);
+    free_value(str);
+    push_value(vm, outMap);
+    break;
+#endif
+}