diff --git a/Userland/Libraries/LibCore/System.cpp b/Userland/Libraries/LibCore/System.cpp
index a3b7a3e1bf..46766b0c90 100644
--- a/Userland/Libraries/LibCore/System.cpp
+++ b/Userland/Libraries/LibCore/System.cpp
@@ -2,6 +2,7 @@
  * Copyright (c) 2021-2022, Andreas Kling <kling@serenityos.org>
  * Copyright (c) 2021, Kenneth Myhra <kennethmyhra@gmail.com>
  * Copyright (c) 2021, Sam Atkins <atkinssj@serenityos.org>
+ * Copyright (c) 2022, Matthias Zimmerman <matthias291999@gmail.com>
  *
  * SPDX-License-Identifier: BSD-2-Clause
  */
@@ -15,6 +16,7 @@
 #include <sys/ioctl.h>
 #include <sys/mman.h>
 #include <sys/ptrace.h>
+#include <sys/time.h>
 #include <termios.h>
 #include <unistd.h>
 
@@ -741,6 +743,18 @@ ErrorOr<struct utsname> uname()
     return uts;
 }
 
+ErrorOr<void> adjtime(const struct timeval* delta, struct timeval* old_delta)
+{
+#ifdef __serenity__
+    int rc = syscall(SC_adjtime, delta, old_delta);
+    HANDLE_SYSCALL_RETURN_VALUE("adjtime"sv, rc, {});
+#else
+    if (::adjtime(delta, old_delta) < 0)
+        return Error::from_syscall("adjtime"sv, -errno);
+    return {};
+#endif
+}
+
 ErrorOr<int> socket(int domain, int type, int protocol)
 {
     auto fd = ::socket(domain, type, protocol);
diff --git a/Userland/Libraries/LibCore/System.h b/Userland/Libraries/LibCore/System.h
index 5b3e7a1c6c..c13a938d55 100644
--- a/Userland/Libraries/LibCore/System.h
+++ b/Userland/Libraries/LibCore/System.h
@@ -18,6 +18,7 @@
 #include <sys/ioctl.h>
 #include <sys/socket.h>
 #include <sys/stat.h>
+#include <sys/time.h>
 #include <sys/utsname.h>
 #include <sys/wait.h>
 #include <termios.h>
@@ -112,6 +113,7 @@ ErrorOr<void> unlink(StringView path);
 ErrorOr<void> utime(StringView path, Optional<struct utimbuf>);
 ErrorOr<struct utsname> uname();
 ErrorOr<Array<int, 2>> pipe2(int flags);
+ErrorOr<void> adjtime(const struct timeval* delta, struct timeval* old_delta);
 
 ErrorOr<int> socket(int domain, int type, int protocol);
 ErrorOr<void> bind(int sockfd, struct sockaddr const*, socklen_t);