diff --git a/include/psa/crypto_sizes.h b/include/psa/crypto_sizes.h
index e4c5a36276..0c4647fae7 100644
--- a/include/psa/crypto_sizes.h
+++ b/include/psa/crypto_sizes.h
@@ -141,7 +141,7 @@
 #define PSA_AEAD_TAG_LENGTH(key_type, key_bits, alg)                        \
     (PSA_AEAD_NONCE_LENGTH(key_type, alg) ?                                 \
      ((alg) & PSA_ALG_AEAD_TAG_LENGTH_MASK) >> PSA_AEAD_TAG_LENGTH_OFFSET : \
-     0)
+     ((void) (key_bits), 0))
 
 /** The maximum tag size for all supported AEAD algorithms, in bytes.
  *