diff --git a/src/test/test-sizeof.c b/src/test/test-sizeof.c
index f4c9916f15..075cc8c5a0 100644
--- a/src/test/test-sizeof.c
+++ b/src/test/test-sizeof.c
@@ -7,6 +7,7 @@
 #include <string.h>
 #include <sys/resource.h>
 #include <sys/socket.h>
+#include <sys/timex.h>
 
 #define __STDC_WANT_IEC_60559_TYPES_EXT__
 #include <float.h>
diff --git a/src/timesync/timesyncd-manager.c b/src/timesync/timesyncd-manager.c
index 031793ea77..012b61d513 100644
--- a/src/timesync/timesyncd-manager.c
+++ b/src/timesync/timesyncd-manager.c
@@ -5,6 +5,7 @@
 #include <netinet/in.h>
 #include <netinet/ip.h>
 #include <resolv.h>
+#include <sys/timex.h>
 #include <unistd.h>
 
 #include "sd-bus.h"