diff --git a/src/secp256k1/src/ecmult.h b/src/secp256k1/src/ecmult.h
index 88475791b..fbcf6a445 100644
--- a/src/secp256k1/src/ecmult.h
+++ b/src/secp256k1/src/ecmult.h
@@ -45,6 +45,7 @@ static void secp256k1_ecmult(const secp256k1_ecmult_context *ctx, secp256k1_gej
 #include "num.h"
 #include "group.h"
 #include "scalar.h"
+#include "scratch.h"
 
 typedef struct {
     /* For accelerating the computation of a*P + b*G: */