diff --git a/include/fcntl.h b/include/fcntl.h
index 53c200044..906c5db3a 100644
--- a/include/fcntl.h
+++ b/include/fcntl.h
@@ -27,7 +27,18 @@
 
 #define AT_SYMLINK_NOFOLLOW  0x100
 #define AT_SYMLINK_FOLLOW    0x400
+
+/* Flag for faccessat(2). */
 #define AT_EACCESS           0x200
 
+/* Flag for unlinkat(2). */
+#if defined(__AT_REMOVEDIR)
+#define AT_REMOVEDIR         __AT_REMOVEDIR
+#elif defined(__APPLE__)
+#define AT_REMOVEDIR         0x080
+#else
+#define AT_REMOVEDIR         0x200
+#endif
+
 int open(const char *fn, int flag, ...);
 int openat(int dirfd, const char *fn, int flag, ...);
diff --git a/include/sys/stat.h b/include/sys/stat.h
index 12e9775ed..2251b3be6 100644
--- a/include/sys/stat.h
+++ b/include/sys/stat.h
@@ -101,6 +101,9 @@ struct stat {
 };
 #endif
 
+int mkdir(const char *pathname, mode_t mode);
+int mkdirat(int dirfd, const char *pathname, mode_t mode);
+
 int chmod(const char *pathname, mode_t mode);
 int fchmodat(int dirfd, const char *pathname, mode_t mode, int flags);
 
diff --git a/include/unistd.h b/include/unistd.h
index 84c5132ed..60888a2d4 100644
--- a/include/unistd.h
+++ b/include/unistd.h
@@ -34,6 +34,7 @@ int close(int fd);
 ssize_t read(int fd, void *buf, size_t size);
 off_t lseek(int fd, off_t offset, int whence);
 int unlink(const char *pathname);
+int rmdir(const char *pathname);
 char *getcwd(char *buffer, size_t size);
 
 int brk(void *addr);
diff --git a/libsrc/_wasm/unistd/mkdir.c b/libsrc/_wasm/unistd/mkdir.c
new file mode 100644
index 000000000..83cd9d13c
--- /dev/null
+++ b/libsrc/_wasm/unistd/mkdir.c
@@ -0,0 +1,38 @@
+#include "sys/stat.h"
+#include "string.h"  // memset, strncmp
+#include "../wasi.h"
+
+extern int __max_preopen_fd;
+
+int mkdir(const char *fn, mode_t mode) {
+  size_t fnlen = strlen(fn);
+  for (int base_fd = 3; base_fd < __max_preopen_fd; ++base_fd) {
+    Prestat prestat;
+    fd_prestat_get(base_fd, &prestat);
+    size_t l = prestat.u.dir.pr_name_len;  // Includes '\0' or not, depending on the environment,
+    char buf[256];
+    fd_prestat_dir_name(base_fd, buf, l);
+    buf[l] = '\0';
+
+    if ((*fn == '/' && *buf != '/') ||
+        (*fn != '/' && strcmp(buf, ".") != 0))
+      continue;
+
+    const char *fn2 = fn;
+    size_t fnlen2 = fnlen;
+
+    if (strncmp(fn, buf, l) == 0 && fn[l] == '/') {
+      fn2 = fn + (l + 1);
+      fnlen2 = fnlen - (l + 1);
+    } else if (l == 1 && *buf == '/' && *fn == '/') {
+      fn2 = fn + 1;
+      fnlen2 = fnlen - 1;
+    }
+
+    Filestat fs;
+    uint32_t result = path_create_directory(base_fd, fn2, fnlen2);
+    if (result == 0)
+      return 0;
+  }
+  return -1;
+}
diff --git a/libsrc/_wasm/unistd/rmdir.c b/libsrc/_wasm/unistd/rmdir.c
new file mode 100644
index 000000000..57d714dff
--- /dev/null
+++ b/libsrc/_wasm/unistd/rmdir.c
@@ -0,0 +1,40 @@
+#include "unistd.h"
+#include "errno.h"
+#include "string.h"
+#include "../wasi.h"
+
+extern int __max_preopen_fd;
+
+int rmdir(const char *fn) {
+  // Search from preopens
+  size_t fnlen = strlen(fn);
+  for (int base_fd = 3; base_fd < __max_preopen_fd; ++base_fd) {
+    Prestat prestat;
+    if (fd_prestat_get(base_fd, &prestat) != 0)
+      break;
+
+    size_t l = prestat.u.dir.pr_name_len;  // Includes '\0' or not, depending on the environment,
+    char buf[256];
+    fd_prestat_dir_name(base_fd, buf, l);
+    buf[l] = '\0';
+
+    if ((*fn == '/' && *buf != '/') ||
+        (*fn != '/' && strcmp(buf, ".") != 0))
+      continue;
+
+    const char *fn2 = fn;
+    size_t fnlen2 = fnlen;
+
+    if (strncmp(fn, buf, l) == 0 && fn[l] == '/') {
+      fn2 = fn + (l + 1);
+      fnlen2 = fnlen - (l + 1);
+    } else if (l == 1 && *buf == '/' && *fn == '/') {
+      fn2 = fn + 1;
+      fnlen2 = fnlen - 1;
+    }
+    int result = path_remove_directory(base_fd, fn2, fnlen2);
+    if (result == 0)
+      return 0;
+  }
+  return -1;
+}
diff --git a/libsrc/_wasm/wasi.h b/libsrc/_wasm/wasi.h
index 027a0e0e8..46655e3c4 100644
--- a/libsrc/_wasm/wasi.h
+++ b/libsrc/_wasm/wasi.h
@@ -110,6 +110,8 @@ WASI_MODULE int path_open(int fd, int dirflags, const char *path, size_t path_le
                          uint64_t fs_rights_base, uint64_t fs_rights_inherting, uint16_t fdflags,
                          uint32_t *opend_fd);
 WASI_MODULE int path_unlink_file(int fd, const char *path, size_t path_len);
+WASI_MODULE int path_create_directory(int fd, const char *path, size_t path_len);
+WASI_MODULE int path_remove_directory(int fd, const char *path, size_t path_len);
 WASI_MODULE int path_filestat_get(int fd, int flags, const char *path, size_t path_len, Filestat *out);
 
 WASI_MODULE int fd_read(int fd, const void *iov, int count, size_t *out);
diff --git a/libsrc/tests/file_test.c b/libsrc/tests/file_test.c
index 5887d7d14..c0b19df8f 100644
--- a/libsrc/tests/file_test.c
+++ b/libsrc/tests/file_test.c
@@ -1,5 +1,6 @@
 #include <stdio.h>
 #include <sys/stat.h>
+#include <unistd.h>
 
 #include <string.h>
 
@@ -44,6 +45,17 @@ TEST(basic_access) {
 
   // remove
   EXPECT_EQ(0, remove(fn));
+
+  // mkdir
+  {
+    const char dn[] = "tmp_ddd";
+    int r;
+    EXPECT_EQ(0, r = mkdir(dn, 0755));
+    if (r == 0) {
+      // rmdir
+      EXPECT_EQ(0, rmdir(dn));
+    }
+  }
 }
 
 TEST(stat) {
@@ -63,13 +75,11 @@ TEST(stat) {
       EXPECT_FALSE(S_ISDIR(st.st_mode));
     }
 
-    // remove(fn);
+    remove(fn);
   }
 
   // Test directory.
-  // TODO: Add `mkdir`
   const char dn[] = "tests";
-  // EXPECT_EQ(0, mkdir(dn, S_IRWXU | S_IRGRP | S_IXGRP | S_IROTH | S_IXOTH));
   {
     struct stat st;
     int r;
@@ -79,7 +89,6 @@ TEST(stat) {
       EXPECT_FALSE(S_ISREG(st.st_mode));
     }
   }
-  // EXPECT_EQ(0, rmdir());
 }
 
 TEST(ungetc) {
diff --git a/libsrc/unistd/_syscall.h b/libsrc/unistd/_syscall.h
index 47abb8f17..80176c447 100644
--- a/libsrc/unistd/_syscall.h
+++ b/libsrc/unistd/_syscall.h
@@ -35,10 +35,13 @@
 #define __NR_kill    62
 #define __NR_getcwd  79
 #define __NR_chdir   80
+#define __NR_mkdir   83
+#define __NR_rmdir   84
 #define __NR_unlink  87
 #define __NR_chmod   90
 #define __NR_time    201
 #define __NR_clock_gettime  228
+#define __NR_mkdirat     258
 #define __NR_newfstatat  262
 
 #elif defined(__aarch64__)
@@ -77,6 +80,7 @@
 #define __NR_unlinkat  35
 #define __NR_fchmodat   53
 #define __NR_clock_gettime  113
+#define __NR_mkdirat     34
 #define __NR_newfstatat  79
 
 #elif defined(__riscv)
@@ -107,6 +111,7 @@
 #define __NR_wait4     260
 #define __NR_fstat     80
 #define __NR_fstatat   79
+#define __NR_mkdirat   34
 #define __NR_unlinkat  35
 
 #else
diff --git a/libsrc/unistd/mkdir.c b/libsrc/unistd/mkdir.c
new file mode 100644
index 000000000..b12a2e5d2
--- /dev/null
+++ b/libsrc/unistd/mkdir.c
@@ -0,0 +1,22 @@
+#include "sys/stat.h"
+#include "_syscall.h"
+#include "errno.h"
+
+#if defined(__NR_mkdir)
+int mkdir(const char *pathname, mode_t mode) {
+  int ret;
+  SYSCALL_RET(__NR_mkdir, ret);
+  if (ret < 0) {
+    errno = -ret;
+    ret = -1;
+  }
+  return ret;
+}
+
+#elif defined(__NR_mkdirat)
+#include "fcntl.h"
+
+int mkdir(const char *pathname, mode_t mode) {
+  return mkdirat(AT_FDCWD, pathname, mode);
+}
+#endif
diff --git a/libsrc/unistd/mkdirat.c b/libsrc/unistd/mkdirat.c
new file mode 100644
index 000000000..c7ec89b0c
--- /dev/null
+++ b/libsrc/unistd/mkdirat.c
@@ -0,0 +1,15 @@
+#include "sys/stat.h"
+#include "_syscall.h"
+#include "errno.h"
+
+#if defined(__NR_mkdirat)
+int mkdirat(int dirfd, const char *pathname, mode_t mode) {
+  int ret;
+  SYSCALL_RET(__NR_mkdirat, ret);
+  if (ret < 0) {
+    errno = -ret;
+    ret = -1;
+  }
+  return ret;
+}
+#endif
diff --git a/libsrc/unistd/rmdir.c b/libsrc/unistd/rmdir.c
new file mode 100644
index 000000000..1691247dc
--- /dev/null
+++ b/libsrc/unistd/rmdir.c
@@ -0,0 +1,23 @@
+#include "sys/stat.h"
+#include "_syscall.h"
+#include "errno.h"
+
+#if defined(__NR_rmdir)
+int rmdir(const char *pathname) {
+ int ret;
+  SYSCALL_RET(__NR_rmdir, ret);
+  if (ret < 0) {
+    errno = -ret;
+    ret = -1;
+  }
+  return ret;
+}
+
+#elif defined(__NR_unlinkat)
+#include "unistd.h"
+#include "fcntl.h"
+
+int rmdir(const char *pathname) {
+  return unlinkat(AT_FDCWD, pathname, AT_REMOVEDIR);
+}
+#endif
diff --git a/src/xcc/main.c b/src/xcc/main.c
index e24683e24..d71313bae 100644
--- a/src/xcc/main.c
+++ b/src/xcc/main.c
@@ -16,6 +16,11 @@
 
 #include "util.h"
 
+  // Hack: AT_REMOVEDIR defined in riscv-gnu-toolchain differs on MacOS and Linux?
+#if defined(__APPLE__) && !defined(__AT_REMOVEDIR)
+#define __AT_REMOVEDIR  0x080
+#endif
+
 static pid_t fork1(void) {
   pid_t pid = fork();
   if (pid < 0)
@@ -635,6 +640,10 @@ static void append_predefined_macros(Vector *cpp_cmd) {
 #if defined(__NO_WCHAR)
   vec_push(cpp_cmd, "-D__NO_WCHAR");
 #endif
+
+#if defined(__AT_REMOVEDIR)
+  vec_push(cpp_cmd, "-D__AT_REMOVEDIR=" STR(__AT_REMOVEDIR));
+#endif
 }
 
 int main(int argc, char *argv[]) {