diff --git a/harvard-kyoto.h b/harvard-kyoto.h
index 10727fb..24c231e 100644
--- a/harvard-kyoto.h
+++ b/harvard-kyoto.h
@@ -3,6 +3,14 @@
 #ifndef __HARVARD_KYOTO_H
 #define __HARVARD_KYOTO_H
 
+#if defined (__cplusplus)
+extern "C" {
+#endif
+
 int encode_harvard_kyoto_to_iast(const char *text, char **out);
 
+#if defined (__cplusplus)
+}
+#endif
+
 #endif /* __HARVARD_KYOTO_H */
diff --git a/transliteration.h b/transliteration.h
index aea9cbb..0f23688 100644
--- a/transliteration.h
+++ b/transliteration.h
@@ -3,6 +3,10 @@
 #ifndef __TRANSLITERATION_H
 #define __TRANSLITERATION_H
 
+#if defined (__cplusplus)
+extern "C" {
+#endif
+
 enum translit_letter_type {
 	VOWEL,
 	CONSONANT,
@@ -30,4 +34,8 @@ static inline int is_devanagari(unsigned int code)
 	return code >= 0x0900 && code <= 0x097f;
 }
 
+#if defined (__cplusplus)
+}
+#endif
+
 #endif /* __TRANSLITERATION_H */
diff --git a/velthuis.h b/velthuis.h
index 22691a0..ac8a020 100644
--- a/velthuis.h
+++ b/velthuis.h
@@ -3,7 +3,15 @@
 #ifndef __VELTHUIS_H
 #define __VELTHUIS_H
 
+#if defined (__cplusplus)
+extern "C" {
+#endif
+
 int encode_velthuis_to_iast(const char *text, char **out);
 int encode_iast_to_velthuis(const char *text, char **out);
 
+#if defined (__cplusplus)
+}
+#endif
+
 #endif /* __VELTHUIS_H */