diff --git a/lib/c/string.zig b/lib/c/string.zig
index da301a19eb..ee4f7eb9b2 100644
--- a/lib/c/string.zig
+++ b/lib/c/string.zig
@@ -1,6 +1,7 @@
 const builtin = @import("builtin");
 const std = @import("std");
 const symbol = @import("../c.zig").symbol;
+const c = std.c;
 
 comptime {
     if (builtin.target.isMuslLibC() or builtin.target.isWasiLibC()) {
@@ -24,6 +25,8 @@ comptime {
         symbol(&strpbrk, "strpbrk");
         symbol(&strstr, "strstr");
         symbol(&strtok, "strtok");
+        symbol(&strdup, "strdup");
+        symbol(&strndup, "strndup");
         // strlen is in compiler_rt
 
         symbol(&strtok_r, "strtok_r");
@@ -164,6 +167,23 @@ fn strtok(noalias maybe_str: ?[*:0]c_char, noalias values: [*:0]const c_char) ca
     return strtok_r(maybe_str, values, &state.str);
 }
 
+fn strdup(str: [*:0]const c_char) callconv(.c) ?[*:0]c_char {
+    const len = std.mem.len(str);
+    const d_opaque = c.malloc(len + 1) orelse return null;
+    const d: [*]c_char = @ptrCast(d_opaque);
+    @memcpy(d[0 .. len + 1], str[0 .. len + 1]);
+    return @ptrCast(d);
+}
+
+fn strndup(str: [*:0]const c_char, n: usize) callconv(.c) ?[*:0]c_char {
+    const len = strnlen(str, n);
+    const d_opaque = c.malloc(len + 1) orelse return null;
+    const d: [*]c_char = @ptrCast(d_opaque);
+    @memcpy(d[0..len], str[0..len]);
+    d[len] = 0;
+    return @ptrCast(d);
+}
+
 // strlen is in compiler_rt
 
 fn strtok_r(noalias maybe_str: ?[*:0]c_char, noalias values: [*:0]const c_char, noalias state: *?[*:0]c_char) callconv(.c) ?[*:0]c_char {
diff --git a/lib/c/wchar.zig b/lib/c/wchar.zig
index b85687e8a7..24aca6b0c8 100644
--- a/lib/c/wchar.zig
+++ b/lib/c/wchar.zig
@@ -5,6 +5,7 @@ const wint_t = std.c.wint_t;
 const wchar_t = std.c.wchar_t;
 
 const symbol = @import("../c.zig").symbol;
+const c = std.c;
 
 comptime {
     if (builtin.target.isMuslLibC() or builtin.target.isWasiLibC()) {
@@ -30,6 +31,7 @@ comptime {
         symbol(&wcspbrk, "wcspbrk");
         symbol(&wcstok, "wcstok");
         symbol(&wcsstr, "wcsstr");
+        symbol(&wcsdup, "wcsdup");
         symbol(&wcswcs, "wcswcs");
     }
 
@@ -189,3 +191,11 @@ fn wcsstr(noalias haystack: [*:0]const wchar_t, noalias needle: [*:0]const wchar
 fn wcswcs(noalias haystack: [*:0]const wchar_t, noalias needle: [*:0]const wchar_t) callconv(.c) ?[*:0]wchar_t {
     return wcsstr(haystack, needle);
 }
+
+fn wcsdup(str: [*:0]const wchar_t) callconv(.c) ?[*:0]wchar_t {
+    const len = wcslen(str);
+    const size = (len + 1) * @sizeOf(wchar_t);
+    const d_opaque = c.malloc(size) orelse return null;
+    const d: [*]wchar_t = @ptrCast(@alignCast(d_opaque));
+    return @ptrCast(wmemcpy(d, str, len + 1));
+}
diff --git a/lib/libc/musl/src/string/strdup.c b/lib/libc/musl/src/string/strdup.c
deleted file mode 100644
index d4c274494f..0000000000
--- a/lib/libc/musl/src/string/strdup.c
+++ /dev/null
@@ -1,10 +0,0 @@
-#include <stdlib.h>
-#include <string.h>
-
-char *strdup(const char *s)
-{
-	size_t l = strlen(s);
-	char *d = malloc(l+1);
-	if (!d) return NULL;
-	return memcpy(d, s, l+1);
-}
diff --git a/lib/libc/musl/src/string/strndup.c b/lib/libc/musl/src/string/strndup.c
deleted file mode 100644
index 617d27ba9e..0000000000
--- a/lib/libc/musl/src/string/strndup.c
+++ /dev/null
@@ -1,12 +0,0 @@
-#include <stdlib.h>
-#include <string.h>
-
-char *strndup(const char *s, size_t n)
-{
-	size_t l = strnlen(s, n);
-	char *d = malloc(l+1);
-	if (!d) return NULL;
-	memcpy(d, s, l);
-	d[l] = 0;
-	return d;
-}
diff --git a/lib/libc/musl/src/string/wcsdup.c b/lib/libc/musl/src/string/wcsdup.c
deleted file mode 100644
index f398e8091c..0000000000
--- a/lib/libc/musl/src/string/wcsdup.c
+++ /dev/null
@@ -1,10 +0,0 @@
-#include <stdlib.h>
-#include <wchar.h>
-
-wchar_t *wcsdup(const wchar_t *s)
-{
-	size_t l = wcslen(s);
-	wchar_t *d = malloc((l+1)*sizeof(wchar_t));
-	if (!d) return NULL;
-	return wmemcpy(d, s, l+1);
-}
diff --git a/lib/std/c.zig b/lib/std/c.zig
index b9d705286e..349b38f612 100644
--- a/lib/std/c.zig
+++ b/lib/std/c.zig
@@ -11136,6 +11136,9 @@ pub extern "c" fn swab(noalias from: *const anyopaque, noalias to: *anyopaque, n
 pub extern "c" fn strncmp(a: [*:0]const c_char, b: [*:0]const c_char, max: usize) c_int;
 pub extern "c" fn strcasecmp(a: [*:0]const c_char, b: [*:0]const c_char) c_int;
 pub extern "c" fn strncasecmp(a: [*:0]const c_char, b: [*:0]const c_char, max: usize) c_int;
+pub extern "c" fn strdup(s: [*:0]const c_char) ?[*:0]c_char;
+pub extern "c" fn strndup(s: [*:0]const c_char, n: usize) ?[*:0]c_char;
+pub extern "c" fn wcsdup(s: [*:0]const wchar_t) ?[*:0]wchar_t;
 
 pub extern "c" fn ffs(i: c_int) c_int;
 pub extern "c" fn ffsl(i: c_long) c_long;
diff --git a/src/libs/musl.zig b/src/libs/musl.zig
index 22d9fbe51f..5f04f32b96 100644
--- a/src/libs/musl.zig
+++ b/src/libs/musl.zig
@@ -1494,14 +1494,11 @@ const src_files = [_][]const u8{
     "musl/src/stdlib/strtod.c",
     "musl/src/stdlib/wcstod.c",
     "musl/src/stdlib/wcstol.c",
-    "musl/src/string/strdup.c",
     "musl/src/string/strerror_r.c",
-    "musl/src/string/strndup.c",
     "musl/src/string/strsignal.c",
     "musl/src/string/strverscmp.c",
     "musl/src/string/wcscasecmp.c",
     "musl/src/string/wcscasecmp_l.c",
-    "musl/src/string/wcsdup.c",
     "musl/src/string/wcsncasecmp.c",
     "musl/src/string/wcsncasecmp_l.c",
     "musl/src/temp/mkdtemp.c",
diff --git a/src/libs/wasi_libc.zig b/src/libs/wasi_libc.zig
index d94f7f6284..07f316b635 100644
--- a/src/libs/wasi_libc.zig
+++ b/src/libs/wasi_libc.zig
@@ -902,13 +902,10 @@ const libc_top_half_src_files = [_][]const u8{
     "musl/src/stdlib/ecvt.c",
     "musl/src/stdlib/fcvt.c",
     "musl/src/stdlib/gcvt.c",
-    "musl/src/string/strdup.c",
     "musl/src/string/strerror_r.c",
-    "musl/src/string/strndup.c",
     "musl/src/string/strverscmp.c",
     "musl/src/string/wcscasecmp.c",
     "musl/src/string/wcscasecmp_l.c",
-    "musl/src/string/wcsdup.c",
     "musl/src/string/wcsncasecmp.c",
     "musl/src/string/wcsncasecmp_l.c",
     "musl/src/thread/default_attr.c",
diff --git a/test/c.zig b/test/c.zig
index d07856d037..bf2c8a5fb2 100644
--- a/test/c.zig
+++ b/test/c.zig
@@ -10,4 +10,5 @@ test {
     _ = @import("c/string.zig");
     _ = @import("c/strings.zig");
     _ = @import("c/unistd.zig");
+    _ = @import("c/wchar.zig");
 }
diff --git a/test/c/string.zig b/test/c/string.zig
index 255c147eae..d9f048bbb6 100644
--- a/test/c/string.zig
+++ b/test/c/string.zig
@@ -10,3 +10,43 @@ test "strncmp" {
     try testing.expect(c.strncmp(@ptrCast("b"), @ptrCast("a"), 1) > 0);
     try testing.expect(c.strncmp(@ptrCast("\xff"), @ptrCast("\x02"), 1) > 0);
 }
+
+test "strdup" {
+    const org: [*:0]const u8 = "a";
+    const cpy_opt = c.strdup(@ptrCast(org));
+    const cpy = cpy_opt orelse return error.OutOfMemory;
+    defer c.free(cpy);
+
+    const cpy_u8: [*:0]u8 = @ptrCast(cpy);
+    try testing.expectEqualStrings(std.mem.span(org), std.mem.span(@as([*:0]const u8, cpy_u8)));
+    try testing.expect(@intFromPtr(cpy_u8) != @intFromPtr(org));
+
+    cpy_u8[0] = 'b';
+    try testing.expectEqualStrings("a", std.mem.span(org));
+    try testing.expectEqualStrings("b", std.mem.span(@as([*:0]const u8, cpy_u8)));
+}
+
+test "strndup" {
+    if (builtin.target.os.tag == .windows) return; // no strndup
+    const org1: [*:0]const u8 = "Hello";
+
+    const copy1_opt = c.strndup(@ptrCast(org1), 100);
+    const copy1 = copy1_opt orelse return error.OutOfMemory;
+    defer c.free(copy1);
+    const copy1_u8: [*:0]u8 = @ptrCast(copy1);
+    try testing.expectEqualStrings("Hello", std.mem.span(@as([*:0]const u8, copy1_u8)));
+
+    const org2: [*:0]const u8 = "Hello World!";
+    const copy2_opt = c.strndup(@ptrCast(org2), 5);
+    const copy2 = copy2_opt orelse return error.OutOfMemory;
+    defer c.free(copy2);
+    const copy2_u8: [*:0]u8 = @ptrCast(copy2);
+    try testing.expectEqualStrings("Hello", std.mem.span(@as([*:0]const u8, copy2_u8)));
+    try testing.expectEqual(@as(usize, 5), std.mem.len(copy2_u8));
+
+    const copy3_opt = c.strndup(@ptrCast(org1), 5);
+    const copy3 = copy3_opt orelse return error.OutOfMemory;
+    defer c.free(copy3);
+    const copy3_u8: [*:0]u8 = @ptrCast(copy3);
+    try testing.expectEqualStrings("Hello", std.mem.span(@as([*:0]const u8, copy3_u8)));
+}
diff --git a/test/c/wchar.zig b/test/c/wchar.zig
new file mode 100644
index 0000000000..1c84bd07be
--- /dev/null
+++ b/test/c/wchar.zig
@@ -0,0 +1,34 @@
+const builtin = @import("builtin");
+const std = @import("std");
+
+const c = std.c;
+const testing = std.testing;
+
+test "wcsdup" {
+    const org: [*:0]const c.wchar_t = &[_:0]c.wchar_t{ 'H', 'e', 'l', 'l', 'o' };
+    const cpy_opt = c.wcsdup(org);
+    const cpy = cpy_opt orelse return error.OutOfMemory;
+    defer c.free(cpy);
+
+    try testing.expectEqual(@as(usize, 5), std.mem.len(@as([*:0]const c.wchar_t, cpy)));
+
+    try testing.expectEqual(@as(c.wchar_t, 'H'), cpy[0]);
+    try testing.expectEqual(@as(c.wchar_t, 'e'), cpy[1]);
+    try testing.expectEqual(@as(c.wchar_t, 'l'), cpy[2]);
+    try testing.expectEqual(@as(c.wchar_t, 'l'), cpy[3]);
+    try testing.expectEqual(@as(c.wchar_t, 'o'), cpy[4]);
+    try testing.expectEqual(@as(c.wchar_t, 0), cpy[5]);
+
+    try testing.expect(@intFromPtr(cpy) != @intFromPtr(org));
+
+    cpy[0] = 'B';
+    try testing.expectEqual(@as(c.wchar_t, 'H'), org[0]);
+    try testing.expectEqual(@as(c.wchar_t, 'B'), cpy[0]);
+}
+
+test "wcsdup empty string" {
+    const org: [*:0]const c.wchar_t = &[_:0]c.wchar_t{};
+    const cpy = c.wcsdup(org) orelse return error.OutOfMemory;
+    defer c.free(cpy);
+    try testing.expectEqual(@as(c.wchar_t, 0), cpy[0]);
+}