diff --git a/.gitignore b/.gitignore
index 5bcbfd2..b70c2f9 100644
--- a/.gitignore
+++ b/.gitignore
@@ -32,6 +32,10 @@ node_modules/
 # `go build -tags withsidecar`. Never commit: it's ~130 MB.
 internal/sidecarassets/assets/sidecar-all.jar
 
+# Simulator companion bundle. Build artifact produced by prepare.sh before
+# `go build -tags withcompanion`. Never commit: it's ~16 MB.
+internal/driver/ioscompanion/companionassets/assets/companion-*.tar.gz
+
 # spec-api compiled output
 pkg/spec/dist/