diff --git a/src/tint/cmd/common/helper.cc b/src/tint/cmd/common/helper.cc
index a1fbaf0..4c11c09 100644
--- a/src/tint/cmd/common/helper.cc
+++ b/src/tint/cmd/common/helper.cc
@@ -276,6 +276,9 @@
             tint::StyledTextPrinter::Create(stderr)->Print(
                 formatter.Format(info.program.Diagnostics()));
         }
+        // Flush any diagnostics written to stderr. We depend on these being emitted to the console
+        // before the program for end-to-end tests.
+        fflush(stderr);
     }
 
     if (!info.program.IsValid()) {