diff --git a/ggml-quants.h b/ggml-quants.h
index 4ad5d69e7..cb7af5961 100644
--- a/ggml-quants.h
+++ b/ggml-quants.h
@@ -201,7 +201,7 @@ typedef struct {
 static_assert(sizeof(block_iq3_xxs) == sizeof(ggml_fp16_t) + 3*(QK_K/8), "wrong iq3_xxs block size/padding");
 
 // 3.4375 bpw
-#define IQ3S_BLOCK_SIZE 16
+#define IQ3S_BLOCK_SIZE 32
 #if QK_K == 64
 #define IQ3S_N_SCALE 2
 #else