diff --git a/src/tests_exhaustive.c b/src/tests_exhaustive.c
index 07e1b667cb..37ed50b5f5 100644
--- a/src/tests_exhaustive.c
+++ b/src/tests_exhaustive.c
@@ -353,6 +353,14 @@ int main(int argc, char** argv) {
     unsigned char rand32[32];
     secp256k1_context *ctx;
 
+    /* Disable buffering for stdout to improve reliability of getting
+     * diagnostic information. Happens right at the start of main because
+     * setbuf must be used before any other operation on the stream. */
+    setbuf(stdout, NULL);
+    /* Also disable buffering for stderr because it's not guaranteed that it's
+     * unbuffered on all systems. */
+    setbuf(stderr, NULL);
+
     /* find iteration count */
     if (argc > 1) {
         count = strtol(argv[1], NULL, 0);