diff --git a/.github/workflows/ci-wasm32-wasi.yml b/.github/workflows/ci-wasm32-wasi.yml
new file mode 100644
index 0000000..5133c1c
--- /dev/null
+++ b/.github/workflows/ci-wasm32-wasi.yml
@@ -0,0 +1,27 @@
+name: CI (wasm32-wasi)
+on:
+  push:
+    branches: [main]
+  pull_request:
+    branches: [main]
+
+jobs:
+  build:
+    runs-on: ubuntu-latest
+    env:
+      GHC_WASM_META: 45f73c3e075fa38efe84055b0dba87996948101d
+    steps:
+      - uses: actions/checkout@v4
+      - uses: cachix/install-nix-action@v31
+
+      - name: Build
+        run: |
+          nix shell "gitlab:haskell-wasm/ghc-wasm-meta?host=gitlab.haskell.org&rev=${GHC_WASM_META}"#{wasmtime,wasm32-wasi-cabal-9_12,wasm32-wasi-ghc-9_12} --command \
+            wasm32-wasi-cabal update
+          nix shell "gitlab:haskell-wasm/ghc-wasm-meta?host=gitlab.haskell.org&rev=${GHC_WASM_META}"#{wasmtime,wasm32-wasi-cabal-9_12,wasm32-wasi-ghc-9_12} --command \
+            wasm32-wasi-cabal build
+
+      - name: Test
+        run: |
+          nix shell "gitlab:haskell-wasm/ghc-wasm-meta?host=gitlab.haskell.org&rev=${GHC_WASM_META}"#{wasmtime,wasm32-wasi-cabal-9_12,wasm32-wasi-ghc-9_12} --command \
+            wasm32-wasi-cabal test --test-wrapper ./tests/run-wasmtime.sh
diff --git a/CHANGELOG.md b/CHANGELOG.md
index 7275f3c..0bfbbab 100644
--- a/CHANGELOG.md
+++ b/CHANGELOG.md
@@ -1,3 +1,7 @@
+## Unreleased
+
+ - Add wasm32-wasi support.
+
 ## Version 0.7.3 (2024-10-11)
 
 - Fix `sysmacros.h` include for GNU/Hurd
diff --git a/cabal.project b/cabal.project
new file mode 100644
index 0000000..3e51bbc
--- /dev/null
+++ b/cabal.project
@@ -0,0 +1,8 @@
+packages: unix-compat.cabal
+
+if arch(wasm32)
+  -- See https://github.com/haskellari/splitmix/pull/73
+  source-repository-package
+    type:     git
+    location: https://github.com/amesgen/splitmix.git
+    tag:      cea9e31bdd849eb0c17611bb99e33d590e126164
diff --git a/cbits/mktemp.c b/cbits/mktemp.c
index b9ec050..a653efa 100644
--- a/cbits/mktemp.c
+++ b/cbits/mktemp.c
@@ -41,13 +41,21 @@
 #include <stdlib.h>
 #include <string.h>
 #include <unistd.h>
+
+#if defined(__wasm__)
+#include <sys/random.h>
+#else
 #include <windows.h>
 #include <wincrypt.h>
 
-static int random(uint32_t *);
+#define open _open
+#define stat _stat
+#endif
+
+static int unixcompat_random(uint32_t *);
 static int _gettemp(char *, int *);
 
-static const unsigned char padchar[] =
+static const char padchar[] =
 "0123456789ABCDEFGHIJKLMNOPQRSTUVWXYZabcdefghijklmnopqrstuvwxyz";
 
 int unixcompat_mkstemp(char *path)
@@ -64,7 +72,7 @@ static int _gettemp(char *path, int *doopen)
 {
     char *start, *trv, *suffp, *carryp;
     char *pad;
-    struct _stat sbuf;
+    struct stat sbuf;
     int rval;
     uint32_t randidx, randval;
     char carrybuf[MAXPATHLEN];
@@ -84,7 +92,7 @@ static int _gettemp(char *path, int *doopen)
 
     /* Fill space with random characters */
     while (trv >= path && *trv == 'X') {
-        if (!random(&randval)) {
+        if (!unixcompat_random(&randval)) {
             /* this should never happen */
             errno = EIO;
             return 0;
@@ -104,7 +112,7 @@ static int _gettemp(char *path, int *doopen)
         for (; trv > path; --trv) {
             if (*trv == '/') {
                 *trv = '\0';
-                rval = _stat(path, &sbuf);
+                rval = stat(path, &sbuf);
                 *trv = '/';
                 if (rval != 0)
                     return (0);
@@ -120,11 +128,11 @@ static int _gettemp(char *path, int *doopen)
     for (;;) {
         if (doopen) {
             if ((*doopen =
-                _open(path, O_CREAT|O_EXCL|O_RDWR, 0600)) >= 0)
+                open(path, O_CREAT|O_EXCL|O_RDWR, 0600)) >= 0)
                 return (1);
             if (errno != EEXIST)
                 return (0);
-        } else if (_stat(path, &sbuf))
+        } else if (stat(path, &sbuf))
             return (errno == ENOENT);
 
         /* If we have a collision, cycle through the space of filenames */
@@ -154,7 +162,14 @@ static int _gettemp(char *path, int *doopen)
     /*NOTREACHED*/
 }
 
-static int random(uint32_t *value)
+#if defined(__wasm__)
+static int unixcompat_random(uint32_t *value)
+{
+    int r = getentropy(value, sizeof(uint32_t));
+    return r == 0 ? 1 : 0;
+}
+#else
+static int unixcompat_random(uint32_t *value)
 {
     /* This handle is never released. Windows will clean up when the process
      * exits. Python takes this approach when emulating /dev/urandom, and if
@@ -171,3 +186,4 @@ static int random(uint32_t *value)
 
     return 1;
 }
+#endif
diff --git a/include/HsUnixCompat.h b/include/HsUnixCompat.h
index 32476d4..0adf96d 100644
--- a/include/HsUnixCompat.h
+++ b/include/HsUnixCompat.h
@@ -4,5 +4,3 @@
 unsigned int unix_major(dev_t dev);
 unsigned int unix_minor(dev_t dev);
 dev_t unix_makedev(unsigned int maj, unsigned int min);
-
-#define NEED_setSymbolicLinkOwnerAndGroup !HAVE_LCHOWN
diff --git a/src/System/PosixCompat/Extensions.hsc b/src/System/PosixCompat/Extensions.hsc
index f9aa7bd..7e637c7 100644
--- a/src/System/PosixCompat/Extensions.hsc
+++ b/src/System/PosixCompat/Extensions.hsc
@@ -12,7 +12,7 @@ module System.PosixCompat.Extensions (
     ) where
 
 
-#ifndef mingw32_HOST_OS
+#if !(defined(mingw32_HOST_OS) || defined(wasm32_HOST_ARCH))
 #include "HsUnixCompat.h"
 #endif
 
@@ -27,7 +27,7 @@ type CMinor = CUInt
 --
 -- The portable implementation always returns @0@.
 deviceMajor :: DeviceID -> CMajor
-#ifdef mingw32_HOST_OS
+#if defined(mingw32_HOST_OS) || defined(wasm32_HOST_ARCH)
 deviceMajor _ = 0
 #else
 deviceMajor dev = unix_major dev
@@ -39,7 +39,7 @@ foreign import ccall unsafe "unix_major" unix_major :: CDev -> CUInt
 --
 -- The portable implementation always returns @0@.
 deviceMinor :: DeviceID -> CMinor
-#ifdef mingw32_HOST_OS
+#if defined(mingw32_HOST_OS) || defined(wasm32_HOST_ARCH)
 deviceMinor _ = 0
 #else
 deviceMinor dev = unix_minor dev
@@ -49,7 +49,7 @@ foreign import ccall unsafe "unix_minor" unix_minor :: CDev -> CUInt
 
 -- | Creates a 'DeviceID' for a device file given a major and minor number.
 makeDeviceID :: CMajor -> CMinor -> DeviceID
-#ifdef mingw32_HOST_OS
+#if defined(mingw32_HOST_OS) || defined(wasm32_HOST_ARCH)
 makeDeviceID _ _ = 0
 #else
 makeDeviceID ma mi = unix_makedev ma mi
diff --git a/src/System/PosixCompat/Files.hsc b/src/System/PosixCompat/Files.hsc
index eddfa1e..9c1bf66 100644
--- a/src/System/PosixCompat/Files.hsc
+++ b/src/System/PosixCompat/Files.hsc
@@ -106,11 +106,11 @@ module System.PosixCompat.Files (
 
 #ifndef mingw32_HOST_OS
 
-#include "HsUnixCompat.h"
+#include "HsUnixConfig.h"
 
 import System.Posix.Files
 
-#if NEED_setSymbolicLinkOwnerAndGroup
+#if !HAVE_LCHOWN
 import System.PosixCompat.Types
 
 setSymbolicLinkOwnerAndGroup :: FilePath -> UserID -> GroupID -> IO ()
diff --git a/src/System/PosixCompat/Process.hs b/src/System/PosixCompat/Process.hs
index 47d3e43..4a2b585 100644
--- a/src/System/PosixCompat/Process.hs
+++ b/src/System/PosixCompat/Process.hs
@@ -8,7 +8,7 @@ module System.PosixCompat.Process (
       getProcessID
     ) where
 
-#ifdef mingw32_HOST_OS
+#if defined(mingw32_HOST_OS)
 
 import System.Posix.Types (ProcessID)
 import System.Win32.Process (getCurrentProcessId)
@@ -16,6 +16,13 @@ import System.Win32.Process (getCurrentProcessId)
 getProcessID :: IO ProcessID
 getProcessID = fromIntegral <$> getCurrentProcessId
 
+#elif defined(wasm32_HOST_ARCH)
+
+import System.Posix.Types (ProcessID)
+
+getProcessID :: IO ProcessID
+getProcessID = pure 1
+
 #else
 
 import System.Posix.Process
diff --git a/src/System/PosixCompat/Temp.hs b/src/System/PosixCompat/Temp.hs
index 8575fc1..63b60f6 100644
--- a/src/System/PosixCompat/Temp.hs
+++ b/src/System/PosixCompat/Temp.hs
@@ -11,13 +11,13 @@ module System.PosixCompat.Temp (
       mkstemp
     ) where
 
-#ifndef mingw32_HOST_OS
+#if !(defined(mingw32_HOST_OS) || defined(wasm32_HOST_ARCH))
 -- Re-export unix package
 
 import System.Posix.Temp
 
 #elif defined(__GLASGOW_HASKELL__)
--- Windows w/ GHC, we have fdToHandle so we
+-- Window/WASM w/ GHC, we have fdToHandle so we
 -- can use our own implementation of mkstemp.
 
 import System.IO (Handle)
diff --git a/tests/run-wasmtime.sh b/tests/run-wasmtime.sh
new file mode 100755
index 0000000..62466df
--- /dev/null
+++ b/tests/run-wasmtime.sh
@@ -0,0 +1,6 @@
+#!/usr/bin/env sh
+
+TMP="$(mktemp -d --suffix=-unix-compat)"
+trap 'rm -rf -- "$TMP"' EXIT
+wasmtime --dir "$TMP::/" "$@"
+exit "$?"
diff --git a/unix-compat.cabal b/unix-compat.cabal
index 85f41fe..c635e45 100644
--- a/unix-compat.cabal
+++ b/unix-compat.cabal
@@ -69,10 +69,13 @@ Library
 
   else
     build-depends: unix      >= 2.7.2.0  && < 2.9
-    include-dirs: include
-    includes: HsUnixCompat.h
-    install-includes: HsUnixCompat.h
-    c-sources: cbits/HsUnixCompat.c
+    if arch(wasm32)
+      c-sources: cbits/mktemp.c
+    else
+      include-dirs: include
+      includes: HsUnixCompat.h
+      install-includes: HsUnixCompat.h
+      c-sources: cbits/HsUnixCompat.c
     if os(solaris)
       cc-options: -DSOLARIS