diff --git a/src/acs/call-funcs.cpp b/src/acs/call-funcs.cpp
index 119238cbe..154a5c37a 100644
--- a/src/acs/call-funcs.cpp
+++ b/src/acs/call-funcs.cpp
@@ -16,7 +16,6 @@
 
 #include "acsvm.hpp"
 
-extern "C" {
 #include "../doomtype.h"
 #include "../doomdef.h"
 #include "../doomstat.h"
@@ -42,7 +41,6 @@ extern "C" {
 #include "../r_skins.h"
 #include "../k_battle.h"
 #include "../k_podium.h"
-}
 
 #include "call-funcs.hpp"
 
diff --git a/src/acs/environment.cpp b/src/acs/environment.cpp
index 139f19eec..0b4932d56 100644
--- a/src/acs/environment.cpp
+++ b/src/acs/environment.cpp
@@ -16,7 +16,6 @@
 
 #include "acsvm.hpp"
 
-extern "C" {
 #include "../doomtype.h"
 #include "../doomdef.h"
 #include "../doomstat.h"
@@ -28,7 +27,6 @@ extern "C" {
 #include "../w_wad.h"
 #include "../z_zone.h"
 #include "../p_local.h"
-}
 
 #include "environment.hpp"
 #include "thread.hpp"
@@ -95,7 +93,7 @@ Environment::Environment()
 	addCodeDataACS0(120, {"",        0, addCallFunc(CallFunc_PlayerRings)});
 
 	addCodeDataACS0(122, {"",        0, addCallFunc(CallFunc_PlayerScore)});
-	
+
 	// 136 to 137: Implemented by ACSVM
 
 	// 157: Implemented by ACSVM
diff --git a/src/acs/interface.cpp b/src/acs/interface.cpp
index 8010a4e4c..bba86c3b9 100644
--- a/src/acs/interface.cpp
+++ b/src/acs/interface.cpp
@@ -18,7 +18,6 @@
 
 #include "acsvm.hpp"
 
-extern "C" {
 #include "interface.h"
 
 #include "../doomtype.h"
@@ -29,7 +28,6 @@ extern "C" {
 #include "../g_game.h"
 #include "../i_system.h"
 #include "../p_saveg.h"
-}
 
 #include "environment.hpp"
 #include "thread.hpp"
diff --git a/src/acs/interface.h b/src/acs/interface.h
index aa2714c46..206414663 100644
--- a/src/acs/interface.h
+++ b/src/acs/interface.h
@@ -18,6 +18,10 @@
 #include "../doomdef.h"
 #include "../doomstat.h"
 
+#ifdef __cplusplus
+extern "C" {
+#endif
+
 /*--------------------------------------------------
 	void ACS_Init(void);
 
@@ -314,5 +318,8 @@ void ACS_Archive(savebuffer_t *save);
 
 void ACS_UnArchive(savebuffer_t *save);
 
+#ifdef __cplusplus
+}
+#endif
 
 #endif // __SRB2_ACS_INTERFACE_H__
diff --git a/src/acs/stream.cpp b/src/acs/stream.cpp
index 746a47f28..3d7fb85bf 100644
--- a/src/acs/stream.cpp
+++ b/src/acs/stream.cpp
@@ -18,13 +18,11 @@
 #include <ostream>
 #include <streambuf>
 
-extern "C" {
 #include "../doomtype.h"
 #include "../doomdef.h"
 #include "../doomstat.h"
 
 #include "../p_saveg.h"
-}
 
 #include "stream.hpp"
 #include "../cxxutil.hpp"
diff --git a/src/acs/thread.hpp b/src/acs/thread.hpp
index b13c0e4f8..61c0d8fe2 100644
--- a/src/acs/thread.hpp
+++ b/src/acs/thread.hpp
@@ -16,7 +16,6 @@
 
 #include "acsvm.hpp"
 
-extern "C" {
 #include "../doomtype.h"
 #include "../doomdef.h"
 #include "../doomstat.h"
@@ -24,7 +23,6 @@ extern "C" {
 #include "../r_defs.h"
 #include "../r_state.h"
 #include "../p_spec.h"
-}
 
 
 namespace srb2::acs {