diff --git a/Source/msg.cpp b/Source/msg.cpp
index 25b2054bf..767cebbf1 100644
--- a/Source/msg.cpp
+++ b/Source/msg.cpp
@@ -3,6 +3,8 @@
  *
  * Implementation of function for sending and receiving network messages.
  */
+#include "msg.h"
+
 #include <climits>
 #include <cmath>
 #include <cstdint>
@@ -38,6 +40,7 @@
 #include "options.h"
 #include "pack.h"
 #include "pfile.h"
+#include "player.h"
 #include "plrmsg.h"
 #include "portals/validation.hpp"
 #include "quests/validation.hpp"
diff --git a/Source/multi.cpp b/Source/multi.cpp
index ddda55ea1..7a5255dd0 100644
--- a/Source/multi.cpp
+++ b/Source/multi.cpp
@@ -3,6 +3,7 @@
  *
  * Implementation of functions for keeping multiplaye games in sync.
  */
+#include "multi.h"
 
 #include <cstddef>
 #include <cstdint>
@@ -20,9 +21,11 @@
 #include "engine/random.hpp"
 #include "engine/world_tile.hpp"
 #include "menu.h"
+#include "msg.h"
 #include "nthread.h"
 #include "options.h"
 #include "pfile.h"
+#include "player.h"
 #include "plrmsg.h"
 #include "qol/chatlog.h"
 #include "storm/storm_net.hpp"
diff --git a/Source/sync.h b/Source/sync.h
index 113b0e962..09a882cb3 100644
--- a/Source/sync.h
+++ b/Source/sync.h
@@ -8,6 +8,9 @@
 #include <cstddef>
 #include <cstdint>
 
+#include "msg.h"
+#include "player.h"
+
 namespace devilution {
 
 size_t sync_all_monsters(std::byte *pbBuf, size_t dwMaxLen);