diff --git a/libc/include/inttypes.h b/libc/include/inttypes.h
index f79c477e..9f6b70da 100644
--- a/libc/include/inttypes.h
+++ b/libc/include/inttypes.h
@@ -49,6 +49,20 @@
 #define PRIuFAST64 __PRI64_PREFIX "u"
 #define PRIuMAX __PRI64_PREFIX "u"
 #define PRIuPTR __PRI64_PREFIX "u"
+#define PRIo8 "o"
+#define PRIo16 "o"
+#define PRIo32 "o"
+#define PRIo64 __PRI64_PREFIX "o"
+#define PRIoLEAST8 "o"
+#define PRIoLEAST16 "o"
+#define PRIoLEAST32 "o"
+#define PRIoLEAST64 __PRI64_PREFIX "o"
+#define PRIoFAST8 "o"
+#define PRIoFAST16 "o"
+#define PRIoFAST32 "o"
+#define PRIoFAST64 __PRI64_PREFIX "o"
+#define PRIoMAX __PRI64_PREFIX "o"
+#define PRIoPTR __PRI64_PREFIX "o"
 #define PRIx8 "x"
 #define PRIx16 "x"
 #define PRIx32 "x"