diff --git a/Documentation/config.txt b/Documentation/config.txt
index 3042d80978..3b6e0901b8 100644
--- a/Documentation/config.txt
+++ b/Documentation/config.txt
@@ -438,6 +438,8 @@ include::config/sequencer.txt[]
 
 include::config/showbranch.txt[]
 
+include::config/sparse.txt[]
+
 include::config/splitindex.txt[]
 
 include::config/ssh.txt[]
diff --git a/Documentation/config/grep.txt b/Documentation/config/grep.txt
index dd51db38e1..a3275ab4b7 100644
--- a/Documentation/config/grep.txt
+++ b/Documentation/config/grep.txt
@@ -28,3 +28,11 @@ grep.fullName::
 grep.fallbackToNoIndex::
 	If set to true, fall back to git grep --no-index if git grep
 	is executed outside of a git repository.  Defaults to false.
+
+ifdef::git-grep[]
+sparse.restrictCmds::
+	See base definition in linkgit:git-config[1]. grep honors
+	sparse.restrictCmds by limiting searches to the sparsity paths in three
+	cases: when searching the working tree, when searching the index with
+	--cached, and when searching a specified commit.
+endif::git-grep[]
diff --git a/Documentation/config/sparse.txt b/Documentation/config/sparse.txt
new file mode 100644
index 0000000000..494761526e
--- /dev/null
+++ b/Documentation/config/sparse.txt
@@ -0,0 +1,20 @@
+sparse.restrictCmds::
+	Only meaningful in conjunction with core.sparseCheckout. This option
+	extends sparse checkouts (which limit which paths are written to the
+	working tree), so that output and operations are also limited to the
+	sparsity paths where possible and implemented. The purpose of this
+	option is to (1) focus output for the user on the portion of the
+	repository that is of interest to them, and (2) enable potentially
+	dramatic performance improvements, especially in conjunction with
+	partial clones.
++
+When this option is true (default), some git commands may limit their behavior
+to the paths specified by the sparsity patterns, or to the intersection of
+those paths and any (like `*.c`) that the user might also specify on the
+command line. When false, the affected commands will work on full trees,
+ignoring the sparsity patterns. For now, only git-grep honors this setting.
++
+Note: commands which export, integrity check, or create history will always
+operate on full trees (e.g. fast-export, format-patch, fsck, commit, etc.),
+unaffected by any sparsity patterns. Also, writing commands such as
+sparse-checkout and read-tree will not be affected by this configuration.
diff --git a/Documentation/git.txt b/Documentation/git.txt
index 2fc92586b5..d857509573 100644
--- a/Documentation/git.txt
+++ b/Documentation/git.txt
@@ -180,6 +180,10 @@ If you just want to run git as if it was started in `<path>` then use
 	Do not perform optional operations that require locks. This is
 	equivalent to setting the `GIT_OPTIONAL_LOCKS` to `0`.
 
+--[no-]restrict-to-sparse-paths::
+	Overrides the sparse.restrictCmds configuration (see
+	linkgit:git-config[1]) for this execution.
+
 --list-cmds=group[,group...]::
 	List commands by group. This is an internal/experimental
 	option and may change or be removed in the future. Supported
diff --git a/Makefile b/Makefile
index 65f8cfb236..778c9e499e 100644
--- a/Makefile
+++ b/Makefile
@@ -982,6 +982,7 @@ LIB_OBJS += sha1-name.o
 LIB_OBJS += shallow.o
 LIB_OBJS += sideband.o
 LIB_OBJS += sigchain.o
+LIB_OBJS += sparse-checkout.o
 LIB_OBJS += split-index.o
 LIB_OBJS += stable-qsort.o
 LIB_OBJS += strbuf.o
diff --git a/builtin/grep.c b/builtin/grep.c
index a32815de0a..3fa364e91c 100644
--- a/builtin/grep.c
+++ b/builtin/grep.c
@@ -25,6 +25,7 @@
 #include "submodule-config.h"
 #include "object-store.h"
 #include "packfile.h"
+#include "sparse-checkout.h"
 
 static char const * const grep_usage[] = {
 	N_("git grep [<options>] [-e] <pattern> [<rev>...] [[--] <path>...]"),
@@ -498,6 +499,7 @@ static int grep_cache(struct grep_opt *opt,
 	int nr;
 	struct strbuf name = STRBUF_INIT;
 	int name_base_len = 0;
+	int sparse_paths_only =	restrict_to_sparse_paths(repo);
 	if (repo->submodule_prefix) {
 		name_base_len = strlen(repo->submodule_prefix);
 		strbuf_addstr(&name, repo->submodule_prefix);
@@ -509,7 +511,7 @@ static int grep_cache(struct grep_opt *opt,
 	for (nr = 0; nr < repo->index->cache_nr; nr++) {
 		const struct cache_entry *ce = repo->index->cache[nr];
 
-		if (ce_skip_worktree(ce))
+		if (sparse_paths_only && ce_skip_worktree(ce))
 			continue;
 
 		strbuf_setlen(&name, name_base_len);
@@ -715,9 +717,10 @@ static int grep_tree(struct grep_opt *opt, const struct pathspec *pathspec,
 		     int is_root_tree)
 {
 	struct pattern_list *patterns = NULL;
+	int sparse_paths_only = restrict_to_sparse_paths(opt->repo);
 	int ret;
 
-	if (is_root_tree)
+	if (is_root_tree && sparse_paths_only)
 		patterns = get_sparsity_patterns(opt->repo);
 
 	ret = do_grep_tree(opt, pathspec, tree, base, tn_len, is_root_tree,
@@ -1258,6 +1261,12 @@ int cmd_grep(int argc, const char **argv, const char *prefix)
 
 	if (!use_index || untracked) {
 		int use_exclude = (opt_exclude < 0) ? use_index : !!opt_exclude;
+
+		if (opt_restrict_to_sparse_paths >= 0) {
+			die(_("--[no-]restrict-to-sparse-paths is incompatible"
+				  " with --no-index and --untracked"));
+		}
+
 		hit = grep_directory(&opt, &pathspec, use_exclude, use_index);
 	} else if (0 <= opt_exclude) {
 		die(_("--[no-]exclude-standard cannot be used for tracked contents"));
diff --git a/contrib/completion/git-completion.bash b/contrib/completion/git-completion.bash
index 9147fba3d5..de12766a70 100644
--- a/contrib/completion/git-completion.bash
+++ b/contrib/completion/git-completion.bash
@@ -3402,6 +3402,8 @@ __git_main ()
 			--namespace=
 			--no-replace-objects
 			--help
+			--restrict-to-sparse-paths
+			--no-restrict-to-sparse-paths
 			"
 			;;
 		*)
diff --git a/git.c b/git.c
index 8bd1d7551d..81206b424c 100644
--- a/git.c
+++ b/git.c
@@ -5,6 +5,7 @@
 #include "run-command.h"
 #include "alias.h"
 #include "shallow.h"
+#include "sparse-checkout.h"
 
 #define RUN_SETUP		(1<<0)
 #define RUN_SETUP_GENTLY	(1<<1)
@@ -311,6 +312,10 @@ static int handle_options(const char ***argv, int *argc, int *envchanged)
 			} else {
 				exit(list_cmds(cmd));
 			}
+		} else if (!strcmp(cmd, "--restrict-to-sparse-paths")) {
+			opt_restrict_to_sparse_paths = 1;
+		} else if (!strcmp(cmd, "--no-restrict-to-sparse-paths")) {
+			opt_restrict_to_sparse_paths = 0;
 		} else {
 			fprintf(stderr, _("unknown option: %s\n"), cmd);
 			usage(git_usage_string);
diff --git a/sparse-checkout.c b/sparse-checkout.c
new file mode 100644
index 0000000000..96c5ed5446
--- /dev/null
+++ b/sparse-checkout.c
@@ -0,0 +1,18 @@
+#include "cache.h"
+#include "config.h"
+#include "sparse-checkout.h"
+
+int opt_restrict_to_sparse_paths = -1;
+
+int restrict_to_sparse_paths(struct repository *repo)
+{
+	int ret;
+
+	if (opt_restrict_to_sparse_paths >= 0)
+		return opt_restrict_to_sparse_paths;
+
+	if (repo_config_get_bool(repo, "sparse.restrictcmds", &ret))
+		ret = 1;
+
+	return ret;
+}
diff --git a/sparse-checkout.h b/sparse-checkout.h
new file mode 100644
index 0000000000..a4805e443a
--- /dev/null
+++ b/sparse-checkout.h
@@ -0,0 +1,11 @@
+#ifndef SPARSE_CHECKOUT_H
+#define SPARSE_CHECKOUT_H
+
+struct repository;
+
+extern int opt_restrict_to_sparse_paths;
+
+/* Whether or not cmds should restrict behavior on sparse paths, in this repo */
+int restrict_to_sparse_paths(struct repository *repo);
+
+#endif /* SPARSE_CHECKOUT_H */
diff --git a/t/t7817-grep-sparse-checkout.sh b/t/t7817-grep-sparse-checkout.sh
index b3109e3479..f93a4f71d1 100755
--- a/t/t7817-grep-sparse-checkout.sh
+++ b/t/t7817-grep-sparse-checkout.sh
@@ -80,10 +80,10 @@ test_expect_success 'setup' '
 	test_path_is_file sub2/a
 '
 
-# The test below checks a special case: the sparsity patterns exclude '/b'
+# The two tests below check a special case: the sparsity patterns exclude '/b'
 # and sparse checkout is enabled, but the path exists in the working tree (e.g.
 # manually created after `git sparse-checkout init`). In this case, grep should
-# skip it.
+# skip the file by default, but not with --no-restrict-to-sparse-paths.
 test_expect_success 'grep in working tree should honor sparse checkout' '
 	cat >expect <<-EOF &&
 	a:text
@@ -93,6 +93,16 @@ test_expect_success 'grep in working tree should honor sparse checkout' '
 	git grep "text" >actual &&
 	test_cmp expect actual
 '
+test_expect_success 'grep w/ --no-restrict-to-sparse-paths for sparsely excluded but present paths' '
+	cat >expect <<-EOF &&
+	a:text
+	b:new-text
+	EOF
+	echo "new-text" >b &&
+	test_when_finished "rm b" &&
+	git --no-restrict-to-sparse-paths grep "text" >actual &&
+	test_cmp expect actual
+'
 
 test_expect_success 'grep unmerged file despite not matching sparsity patterns' '
 	cat >expect <<-EOF &&
@@ -157,7 +167,7 @@ test_expect_success 'grep <tree-ish> should ignore sparsity patterns' '
 '
 
 # Note that sub2/ is present in the worktree but it is excluded by the sparsity
-# patterns, so grep should not recurse into it.
+# patterns, so grep should only recurse into it with --no-restrict-to-sparse-paths.
 test_expect_success 'grep --recurse-submodules should honor sparse checkout in submodule' '
 	cat >expect <<-EOF &&
 	a:text
@@ -166,6 +176,15 @@ test_expect_success 'grep --recurse-submodules should honor sparse checkout in s
 	git grep --recurse-submodules "text" >actual &&
 	test_cmp expect actual
 '
+test_expect_success 'grep --recurse-submodules should search in excluded submodules w/ --no-restrict-to-sparse-paths' '
+	cat >expect <<-EOF &&
+	a:text
+	sub/B/b:text
+	sub2/a:text
+	EOF
+	git --no-restrict-to-sparse-paths grep --recurse-submodules "text" >actual &&
+	test_cmp expect actual
+'
 
 test_expect_success 'grep --recurse-submodules --cached should honor sparse checkout in submodule' '
 	cat >expect <<-EOF &&
@@ -192,4 +211,111 @@ test_expect_success 'grep --recurse-submodules <commit-ish> should honor sparse
 	test_cmp expect_tag-to-commit actual_tag-to-commit
 '
 
+for cmd in 'git --no-restrict-to-sparse-paths grep' \
+	   'git -c sparse.restrictCmds=false grep' \
+	   'git -c sparse.restrictCmds=true --no-restrict-to-sparse-paths grep'
+do
+
+	test_expect_success "$cmd --cached should ignore sparsity patterns" '
+		cat >expect <<-EOF &&
+		a:text
+		b:text
+		dir/c:text
+		EOF
+		$cmd --cached "text" >actual &&
+		test_cmp expect actual
+	'
+
+	test_expect_success "$cmd <commit-ish> should ignore sparsity patterns" '
+		commit=$(git rev-parse HEAD) &&
+		cat >expect_commit <<-EOF &&
+		$commit:a:text
+		$commit:b:text
+		$commit:dir/c:text
+		EOF
+		cat >expect_tag-to-commit <<-EOF &&
+		tag-to-commit:a:text
+		tag-to-commit:b:text
+		tag-to-commit:dir/c:text
+		EOF
+		$cmd "text" $commit >actual_commit &&
+		test_cmp expect_commit actual_commit &&
+		$cmd "text" tag-to-commit >actual_tag-to-commit &&
+		test_cmp expect_tag-to-commit actual_tag-to-commit
+	'
+done
+
+test_expect_success 'grep --recurse-submodules --cached w/ --no-restrict-to-sparse-paths' '
+	cat >expect <<-EOF &&
+	a:text
+	b:text
+	dir/c:text
+	sub/A/a:text
+	sub/B/b:text
+	sub2/a:text
+	EOF
+	git --no-restrict-to-sparse-paths grep --recurse-submodules --cached \
+		"text" >actual &&
+	test_cmp expect actual
+'
+
+test_expect_success 'grep --recurse-submodules <commit-ish> w/ --no-restrict-to-sparse-paths' '
+	commit=$(git rev-parse HEAD) &&
+	cat >expect_commit <<-EOF &&
+	$commit:a:text
+	$commit:b:text
+	$commit:dir/c:text
+	$commit:sub/A/a:text
+	$commit:sub/B/b:text
+	$commit:sub2/a:text
+	EOF
+	cat >expect_tag-to-commit <<-EOF &&
+	tag-to-commit:a:text
+	tag-to-commit:b:text
+	tag-to-commit:dir/c:text
+	tag-to-commit:sub/A/a:text
+	tag-to-commit:sub/B/b:text
+	tag-to-commit:sub2/a:text
+	EOF
+	git --no-restrict-to-sparse-paths grep --recurse-submodules "text" \
+		$commit >actual_commit &&
+	test_cmp expect_commit actual_commit &&
+	git --no-restrict-to-sparse-paths grep --recurse-submodules "text" \
+		tag-to-commit >actual_tag-to-commit &&
+	test_cmp expect_tag-to-commit actual_tag-to-commit
+'
+
+test_expect_success 'should respect the sparse.restrictCmds values from submodules' '
+	cat >expect <<-EOF &&
+	a:text
+	sub/A/a:text
+	sub/B/b:text
+	EOF
+	test_config -C sub sparse.restrictCmds false &&
+	git grep --cached --recurse-submodules "text" >actual &&
+	test_cmp expect actual
+'
+
+test_expect_success 'should propagate --[no]-restrict-to-sparse-paths to submodules' '
+	cat >expect <<-EOF &&
+	a:text
+	b:text
+	dir/c:text
+	sub/A/a:text
+	sub/B/b:text
+	sub2/a:text
+	EOF
+	test_config -C sub sparse.restrictCmds true &&
+	git --no-restrict-to-sparse-paths grep --cached --recurse-submodules "text" >actual &&
+	test_cmp expect actual
+'
+
+for opt in '--untracked' '--no-index'
+do
+	test_expect_success "--[no]-restrict-to-sparse-paths and $opt are incompatible" "
+		test_must_fail git --restrict-to-sparse-paths grep $opt . 2>actual &&
+		test_i18ngrep 'restrict-to-sparse-paths is incompatible with' actual
+	"
+done
+
 test_done
diff --git a/t/t9902-completion.sh b/t/t9902-completion.sh
index 8425b9a531..a8c2ac9d70 100755
--- a/t/t9902-completion.sh
+++ b/t/t9902-completion.sh
@@ -1928,6 +1928,8 @@ test_expect_success 'double dash "git" itself' '
 	--namespace=
 	--no-replace-objects Z
 	--help Z
+	--restrict-to-sparse-paths Z
+	--no-restrict-to-sparse-paths Z
 	EOF
 '
 
@@ -1970,7 +1972,7 @@ test_expect_success 'general options' '
 	test_completion "git --nam" "--namespace=" &&
 	test_completion "git --bar" "--bare " &&
 	test_completion "git --inf" "--info-path " &&
-	test_completion "git --no-r" "--no-replace-objects "
+	test_completion "git --no-rep" "--no-replace-objects "
 '
 
 test_expect_success 'general options plus command' '
