diff --git a/tests/functional/eval.sh b/tests/functional/eval.sh
index c6a475cd0..502170d14 100644
--- a/tests/functional/eval.sh
+++ b/tests/functional/eval.sh
@@ -52,3 +52,7 @@ fi
 
 # Test --arg-from-stdin.
 [[ "$(echo bla | nix eval --raw --arg-from-stdin foo --expr '{ foo }: { inherit foo; }' foo)" = bla ]]
+
+# Test that unknown settings are warned about
+out="$(expectStderr 0 nix eval --option foobar baz --expr '""' --raw)"
+[[ "$(echo "$out" | grep foobar | wc -l)" = 1 ]]
diff --git a/tests/functional/misc.sh b/tests/functional/misc.sh
index af96d20bd..d4379b7ce 100644
--- a/tests/functional/misc.sh
+++ b/tests/functional/misc.sh
@@ -30,3 +30,12 @@ expectStderr 1 nix-instantiate --eval -E '[]' -A 'x' | grepQuiet "should be a se
 expectStderr 1 nix-instantiate --eval -E '{}' -A '1' | grepQuiet "should be a list"
 expectStderr 1 nix-instantiate --eval -E '{}' -A '.' | grepQuiet "empty attribute name"
 expectStderr 1 nix-instantiate --eval -E '[]' -A '1' | grepQuiet "out of range"
+
+# Unknown setting warning
+# NOTE(cole-h): behavior is different depending on the order, which is why we test an unknown option
+# before and after the `'{}'`!
+out="$(expectStderr 0 nix-instantiate --option foobar baz --expr '{}')"
+[[ "$(echo "$out" | grep foobar | wc -l)" = 1 ]]
+
+out="$(expectStderr 0 nix-instantiate '{}' --option foobar baz --expr )"
+[[ "$(echo "$out" | grep foobar | wc -l)" = 1 ]]