diff --git a/builtin/log.c b/builtin/log.c
index c211d66d1d..8e2e9912ab 100644
--- a/builtin/log.c
+++ b/builtin/log.c
@@ -661,6 +661,11 @@ int cmd_show(int argc, const char **argv, const char *prefix)
 	init_log_defaults();
 	git_config(git_log_config, NULL);
 
+	if (the_repository->gitdir) {
+		prepare_repo_settings(the_repository);
+		the_repository->settings.command_requires_full_index = 0;
+	}
+
 	memset(&match_all, 0, sizeof(match_all));
 	repo_init_revisions(the_repository, &rev, prefix);
 	git_config(grep_config, &rev.grep_filter);
diff --git a/t/t1092-sparse-checkout-compatibility.sh b/t/t1092-sparse-checkout-compatibility.sh
index 74792b5ebb..3506c0216f 100755
--- a/t/t1092-sparse-checkout-compatibility.sh
+++ b/t/t1092-sparse-checkout-compatibility.sh
@@ -1159,12 +1159,21 @@ test_expect_success 'show (cached blobs/trees)' '
 	test_sparse_match git show :folder1/a &&
 
 	# Asking "git show" for directories in the index
-	# does not work as implemented. The error message is
-	# different for a full checkout and a sparse checkout
-	# when the directory is outside of the cone.
+	# had different behavior depending on the existence
+	# of a sparse index.
 	test_all_match test_must_fail git show :deep/ &&
 	test_must_fail git -C full-checkout show :folder1/ &&
-	test_sparse_match test_must_fail git show :folder1/
+	test_must_fail git -C sparse-checkout show :folder1/ &&
+
+	git -C sparse-index show :folder1/ >actual &&
+	git -C full-checkout show HEAD:folder1 >expect &&
+
+	# The output of "git show" includes the way we referenced the
+	# objects, so strip that out.
+	test_line_count = 4 actual &&
+	tail -n 2 actual >actual-trunc &&
+	tail -n 2 expect >expect-trunc &&
+	test_cmp expect-trunc actual-trunc
 '
 
 test_expect_success 'submodule handling' '
@@ -1388,6 +1397,13 @@ test_expect_success 'sparse index is not expanded: diff' '
 	ensure_not_expanded diff --cached
 '
 
+test_expect_success 'sparse index is not expanded: show' '
+	init_repos &&
+
+	ensure_not_expanded show :a &&
+	ensure_not_expanded show :deep/a
+'
+
 test_expect_success 'sparse index is not expanded: update-index' '
 	init_repos &&