diff --git a/Userland/Libraries/LibCore/System.cpp b/Userland/Libraries/LibCore/System.cpp
index d662d5d705b..bd60d29997d 100644
--- a/Userland/Libraries/LibCore/System.cpp
+++ b/Userland/Libraries/LibCore/System.cpp
@@ -330,7 +330,9 @@ ErrorOr<void> sigaction(int signal, struct sigaction const* action, struct sigac
     return {};
 }
 
-#if defined(AK_OS_BSD_GENERIC)
+#if defined(AK_OS_SOLARIS)
+ErrorOr<SIG_TYP> signal(int signal, SIG_TYP handler)
+#elif defined(AK_OS_BSD_GENERIC)
 ErrorOr<sig_t> signal(int signal, sig_t handler)
 #else
 ErrorOr<sighandler_t> signal(int signal, sighandler_t handler)
diff --git a/Userland/Libraries/LibCore/System.h b/Userland/Libraries/LibCore/System.h
index bafa88c4675..5cf34878259 100644
--- a/Userland/Libraries/LibCore/System.h
+++ b/Userland/Libraries/LibCore/System.h
@@ -93,7 +93,9 @@ ErrorOr<int> accept4(int sockfd, struct sockaddr*, socklen_t*, int flags);
 #endif
 
 ErrorOr<void> sigaction(int signal, struct sigaction const* action, struct sigaction* old_action);
-#if defined(AK_OS_BSD_GENERIC)
+#if defined(AK_OS_SOLARIS)
+ErrorOr<SIG_TYP> signal(int signal, SIG_TYP handler);
+#elif defined(AK_OS_BSD_GENERIC)
 ErrorOr<sig_t> signal(int signal, sig_t handler);
 #else
 ErrorOr<sighandler_t> signal(int signal, sighandler_t handler);