diff --git a/ci/install-rust.sh b/ci/install-rust.sh
index d7e2be8070dc0..d7a035af21689 100644
--- a/ci/install-rust.sh
+++ b/ci/install-rust.sh
@@ -13,12 +13,12 @@ fi
 if [ "$OS" = "windows" ]; then
   : "${TARGET?The TARGET environment variable must be set.}"
   rustup set profile minimal
-  rustup update --force $toolchain-"$TARGET"
-  rustup default $toolchain-"$TARGET"
+  rustup update --force "$toolchain-$TARGET"
+  rustup default "$toolchain-$TARGET"
 else
   rustup set profile minimal
-  rustup update --force $toolchain
-  rustup default $toolchain
+  rustup update --force "$toolchain"
+  rustup default "$toolchain"
 fi
 
 if [ -n "$TARGET" ]; then