diff --git a/src/dec/vp8.c b/src/dec/vp8.c
index c17f575c..9f417ac8 100644
--- a/src/dec/vp8.c
+++ b/src/dec/vp8.c
@@ -12,6 +12,10 @@
 #include <stdlib.h>
 #include "vp8i.h"
 
+#if defined(__cplusplus) || defined(c_plusplus)
+extern "C" {
+#endif
+
 //-----------------------------------------------------------------------------
 // VP8Decoder
 
@@ -658,3 +662,9 @@ void VP8Clear(VP8Decoder* const dec) {
   memset(&dec->br_, 0, sizeof(dec->br_));
   dec->ready_ = 0;
 }
+
+//-----------------------------------------------------------------------------
+
+#if defined(__cplusplus) || defined(c_plusplus)
+}    // extern "C"
+#endif
diff --git a/src/enc/config.c b/src/enc/config.c
index 6a4cd1f9..86ef5ce2 100644
--- a/src/enc/config.c
+++ b/src/enc/config.c
@@ -12,6 +12,10 @@
 #include <assert.h>
 #include "webp/encode.h"
 
+#if defined(__cplusplus) || defined(c_plusplus)
+extern "C" {
+#endif
+
 //-----------------------------------------------------------------------------
 // WebPConfig
 //-----------------------------------------------------------------------------
@@ -105,3 +109,7 @@ int WebPValidateConfig(const WebPConfig* const config) {
 }
 
 //-----------------------------------------------------------------------------
+
+#if defined(__cplusplus) || defined(c_plusplus)
+}    // extern "C"
+#endif
diff --git a/src/enc/filter.c b/src/enc/filter.c
index cf845e0d..5a243b17 100644
--- a/src/enc/filter.c
+++ b/src/enc/filter.c
@@ -12,6 +12,10 @@
 #include <math.h>
 #include "vp8enci.h"
 
+#if defined(__cplusplus) || defined(c_plusplus)
+extern "C" {
+#endif
+
 // NOTE: clip1, tables and InitTables are repeated entries of dsp.c
 static uint8_t abs0[255 + 255 + 1];     // abs(i)
 static uint8_t abs1[255 + 255 + 1];     // abs(i)>>1
@@ -368,3 +372,7 @@ void VP8AdjustFilterStrength(VP8EncIterator* const it) {
     enc->dqm_[s].fstrength_ = best_level;
   }
 }
+
+#if defined(__cplusplus) || defined(c_plusplus)
+}    // extern "C"
+#endif