diff --git a/crypto_sign/dilithium2/clean/api.h b/crypto_sign/dilithium2/clean/api.h
index 176824a1..6bba4842 100644
--- a/crypto_sign/dilithium2/clean/api.h
+++ b/crypto_sign/dilithium2/clean/api.h
@@ -1,6 +1,7 @@
 #ifndef PQCLEAN_DILITHIUM2_CLEAN_API_H
 #define PQCLEAN_DILITHIUM2_CLEAN_API_H
 
+#include <stddef.h>
 #include <stdint.h>
 
 #define MODE 2
diff --git a/crypto_sign/dilithium3/clean/api.h b/crypto_sign/dilithium3/clean/api.h
index 2af3c081..411160d8 100644
--- a/crypto_sign/dilithium3/clean/api.h
+++ b/crypto_sign/dilithium3/clean/api.h
@@ -1,6 +1,7 @@
 #ifndef PQCLEAN_DILITHIUM3_CLEAN_API_H
 #define PQCLEAN_DILITHIUM3_CLEAN_API_H
 
+#include <stddef.h>
 #include <stdint.h>
 
 
diff --git a/crypto_sign/dilithium4/clean/api.h b/crypto_sign/dilithium4/clean/api.h
index 608ccd74..c6dac283 100644
--- a/crypto_sign/dilithium4/clean/api.h
+++ b/crypto_sign/dilithium4/clean/api.h
@@ -1,6 +1,7 @@
 #ifndef PQCLEAN_DILITHIUM4_CLEAN_API_H
 #define PQCLEAN_DILITHIUM4_CLEAN_API_H
 
+#include <stddef.h>
 #include <stdint.h>
 
 #define PQCLEAN_DILITHIUM4_CLEAN_CRYPTO_PUBLICKEYBYTES 1760U
diff --git a/test/crypto_kem/functest.c b/test/crypto_kem/functest.c
index 3b4e7008..16650b21 100644
--- a/test/crypto_kem/functest.c
+++ b/test/crypto_kem/functest.c
@@ -1,10 +1,9 @@
+#include "api.h"
+#include "randombytes.h"
 #include <stdint.h>
 #include <stdio.h>
 #include <string.h>
 
-#include "api.h"
-#include "randombytes.h"
-
 #ifndef NTESTS
 #define NTESTS 5
 #endif
diff --git a/test/crypto_sign/functest.c b/test/crypto_sign/functest.c
index bd729194..43d5b7b2 100644
--- a/test/crypto_sign/functest.c
+++ b/test/crypto_sign/functest.c
@@ -1,11 +1,10 @@
+#include "api.h"
+#include "randombytes.h"
 #include <stddef.h>
 #include <stdint.h>
 #include <stdio.h>
 #include <string.h>
 
-#include "api.h"
-#include "randombytes.h"
-
 #ifndef NTESTS
 #define NTESTS 5
 #endif