diff --git a/lib/bitmap.h b/lib/bitmap.h
index c2bd99bd..6dc0f403 100644
--- a/lib/bitmap.h
+++ b/lib/bitmap.h
@@ -1,5 +1,5 @@
-#if !defined(_BITMAP_H)
-#define _BITMAP_H
+#if !defined(_TOYWASM_BITMAP_H)
+#define _TOYWASM_BITMAP_H
 
 #include <stdbool.h>
 #include <stdint.h>
@@ -13,4 +13,4 @@ void bitmap_free(struct bitmap *b);
 void bitmap_set(struct bitmap *b, uint32_t idx);
 bool bitmap_test(const struct bitmap *b, uint32_t idx);
 
-#endif /* !defined(_BITMAP_H) */
+#endif /* !defined(_TOYWASM_BITMAP_H) */
diff --git a/lib/cell.h b/lib/cell.h
index 0576a1e4..8271e732 100644
--- a/lib/cell.h
+++ b/lib/cell.h
@@ -1,5 +1,5 @@
-#if !defined(_CELL_H)
-#define _CELL_H
+#if !defined(_TOYWASM_CELL_H)
+#define _TOYWASM_CELL_H
 
 #include <stdint.h>
 
@@ -52,4 +52,4 @@ void cells_zero(struct cell *cells, uint32_t ncells);
 void cells_copy(struct cell *dst, const struct cell *src, uint32_t ncells);
 void cells_move(struct cell *dst, const struct cell *src, uint32_t ncells);
 
-#endif /* !defined(_CELL_H) */
+#endif /* !defined(_TOYWASM_CELL_H) */
diff --git a/lib/endian.h b/lib/endian.h
index 9c640a18..8c767396 100644
--- a/lib/endian.h
+++ b/lib/endian.h
@@ -1,5 +1,5 @@
-#if !defined(_ENDIAN_H)
-#define _ENDIAN_H
+#if !defined(_TOYWASM_ENDIAN_H)
+#define _TOYWASM_ENDIAN_H
 #include <stdint.h>
 
 uint8_t le8_to_host(uint8_t v);
@@ -67,4 +67,4 @@ lef64_decode(const void *p)
 double lef64_decode(const void *p);
 #endif
 
-#endif /* !defined(_ENDIAN_H) */
+#endif /* !defined(_TOYWASM_ENDIAN_H) */
diff --git a/lib/lock.h b/lib/lock.h
index c085c110..ca73dd46 100644
--- a/lib/lock.h
+++ b/lib/lock.h
@@ -1,5 +1,5 @@
-#if !defined(_LOCK_H)
-#define _LOCK_H
+#if !defined(_TOYWASM_LOCK_H)
+#define _TOYWASM_LOCK_H
 
 #include "toywasm_config.h"
 
@@ -73,4 +73,4 @@ void toywasm_cv_broadcast(pthread_cond_t *cv, struct toywasm_mutex *lock)
 #define toywasm_cv_signal(a, lk)
 #define toywasm_cv_broadcast(a, lk)
 #endif /* defined(USE_PTHREAD) */
-#endif /* !defined(_LOCK_H) */
+#endif /* !defined(_TOYWASM_LOCK_H) */
diff --git a/lib/options.h b/lib/options.h
index efba465d..59860e77 100644
--- a/lib/options.h
+++ b/lib/options.h
@@ -1,5 +1,5 @@
-#if !defined(_OPTIONS_H)
-#define _OPTIONS_H
+#if !defined(_TOYWASM_OPTIONS_H)
+#define _TOYWASM_OPTIONS_H
 
 #include <stdbool.h>
 #include <stdint.h>
@@ -20,4 +20,4 @@ struct exec_options {
 
 void load_options_set_defaults(struct load_options *opts);
 void exec_options_set_defaults(struct exec_options *opts);
-#endif /* !defined(_OPTIONS_H) */
+#endif /* !defined(_TOYWASM_OPTIONS_H) */
diff --git a/lib/report.h b/lib/report.h
index 7eeca3bd..190eaf27 100644
--- a/lib/report.h
+++ b/lib/report.h
@@ -1,5 +1,5 @@
-#if !defined(_REPORT_H)
-#define _REPORT_H
+#if !defined(_TOYWASM_REPORT_H)
+#define _TOYWASM_REPORT_H
 
 #include <stdarg.h>
 
@@ -12,4 +12,4 @@ void report_error(struct report *r, const char *fmt, ...)
         __attribute__((__format__(__printf__, 2, 3)));
 void report_init(struct report *r);
 void report_clear(struct report *r);
-#endif /* defined(_REPORT_H) */
+#endif /* defined(_TOYWASM_REPORT_H) */
diff --git a/lib/type.h b/lib/type.h
index df9bb742..958dc5dc 100644
--- a/lib/type.h
+++ b/lib/type.h
@@ -1,5 +1,5 @@
-#if !defined(_TYPE_H)
-#define _TYPE_H
+#if !defined(_TOYWASM_TYPE_H)
+#define _TOYWASM_TYPE_H
 
 #include <stdbool.h>
 #include <stdint.h>
@@ -572,4 +572,4 @@ void clear_resulttype(struct resulttype *rt);
 void set_name_cstr(struct name *name, char *cstr);
 void clear_name(struct name *name);
 
-#endif /* defined(_TYPE_H) */
+#endif /* defined(_TOYWASM_TYPE_H) */
diff --git a/lib/valtype.h b/lib/valtype.h
index f7453b10..e69b721b 100644
--- a/lib/valtype.h
+++ b/lib/valtype.h
@@ -1,5 +1,5 @@
-#if !defined(_VALTYPE_H)
-#define _VALTYPE_H
+#if !defined(_TOYWASM_VALTYPE_H)
+#define _TOYWASM_VALTYPE_H
 
 enum valtype {
         /* numtype */
@@ -20,4 +20,4 @@ enum valtype {
         TYPE_UNKNOWN = 0xff,
 };
 
-#endif /* !defined(_VALTYPE_H) */
+#endif /* !defined(_TOYWASM_VALTYPE_H) */
diff --git a/lib/vec.h b/lib/vec.h
index d0df67be..3ba6ea03 100644
--- a/lib/vec.h
+++ b/lib/vec.h
@@ -1,5 +1,5 @@
-#if !defined(_VEC_H)
-#define _VEC_H
+#if !defined(_TOYWASM_VEC_H)
+#define _TOYWASM_VEC_H
 
 #include <stdint.h>
 
@@ -42,4 +42,4 @@ void _vec_free(void *vec);
 #define VEC_POP(v) (&v.p[--v.lsize])
 #define VEC_POP_DROP(v) v.lsize--
 
-#endif /* !defined(_VEC_H) */
+#endif /* !defined(_TOYWASM_VEC_H) */