diff --git a/Source/santad/ProcessTree/process.h b/Source/santad/ProcessTree/process.h
index 72ef0c448..3afbf42e0 100644
--- a/Source/santad/ProcessTree/process.h
+++ b/Source/santad/ProcessTree/process.h
@@ -14,6 +14,8 @@
 #ifndef SANTA__SANTAD_PROCESSTREE_PROCESS_H
 #define SANTA__SANTAD_PROCESSTREE_PROCESS_H
 
+#include <sys/types.h>
+
 #include <cstdint>
 #include <memory>
 #include <string>
diff --git a/Source/santad/ProcessTree/process_tree.cc b/Source/santad/ProcessTree/process_tree.cc
index 3954033cb..6b57598d2 100644
--- a/Source/santad/ProcessTree/process_tree.cc
+++ b/Source/santad/ProcessTree/process_tree.cc
@@ -13,6 +13,8 @@
 /// limitations under the License.
 #include "Source/santad/ProcessTree/process_tree.h"
 
+#include <sys/types.h>
+
 #include <algorithm>
 #include <cassert>
 #include <cstdint>