diff --git a/Documentation/git-grep.txt b/Documentation/git-grep.txt
index 0ecea6e491..17aa1ba702 100644
--- a/Documentation/git-grep.txt
+++ b/Documentation/git-grep.txt
@@ -26,6 +26,7 @@ SYNOPSIS
 	   [--threads <num>]
 	   [-f <file>] [-e] <pattern>
 	   [--and|--or|--not|(|)|-e <pattern>...]
+	   [--recurse-submodules]
 	   [ [--[no-]exclude-standard] [--cached | --no-index | --untracked] | <tree>...]
 	   [--] [<pathspec>...]
 
@@ -88,6 +89,10 @@ OPTIONS
 	mechanism.  Only useful when searching files in the current directory
 	with `--no-index`.
 
+--recurse-submodules::
+	Recursively search in each submodule that has been initialized and
+	checked out in the repository.
+
 -a::
 --text::
 	Process binary files as if they were text.
diff --git a/builtin/grep.c b/builtin/grep.c
index 8887b6addb..dca0be6475 100644
--- a/builtin/grep.c
+++ b/builtin/grep.c
@@ -18,12 +18,20 @@
 #include "quote.h"
 #include "dir.h"
 #include "pathspec.h"
+#include "submodule.h"
 
 static char const * const grep_usage[] = {
 	N_("git grep [<options>] [-e] <pattern> [<rev>...] [[--] <path>...]"),
 	NULL
 };
 
+static const char *super_prefix;
+static int recurse_submodules;
+static struct argv_array submodule_options = ARGV_ARRAY_INIT;
+
+static int grep_submodule_launch(struct grep_opt *opt,
+				 const struct grep_source *gs);
+
 #define GREP_NUM_THREADS_DEFAULT 8
 static int num_threads;
 
@@ -174,7 +182,10 @@ static void *run(void *arg)
 			break;
 
 		opt->output_priv = w;
-		hit |= grep_source(opt, &w->source);
+		if (w->source.type == GREP_SOURCE_SUBMODULE)
+			hit |= grep_submodule_launch(opt, &w->source);
+		else
+			hit |= grep_source(opt, &w->source);
 		grep_source_clear_data(&w->source);
 		work_done(w);
 	}
@@ -300,6 +311,10 @@ static int grep_sha1(struct grep_opt *opt, const unsigned char *sha1,
 	if (opt->relative && opt->prefix_length) {
 		quote_path_relative(filename + tree_name_len, opt->prefix, &pathbuf);
 		strbuf_insert(&pathbuf, 0, filename, tree_name_len);
+	} else if (super_prefix) {
+		strbuf_add(&pathbuf, filename, tree_name_len);
+		strbuf_addstr(&pathbuf, super_prefix);
+		strbuf_addstr(&pathbuf, filename + tree_name_len);
 	} else {
 		strbuf_addstr(&pathbuf, filename);
 	}
@@ -328,10 +343,13 @@ static int grep_file(struct grep_opt *opt, const char *filename)
 {
 	struct strbuf buf = STRBUF_INIT;
 
-	if (opt->relative && opt->prefix_length)
+	if (opt->relative && opt->prefix_length) {
 		quote_path_relative(filename, opt->prefix, &buf);
-	else
+	} else {
+		if (super_prefix)
+			strbuf_addstr(&buf, super_prefix);
 		strbuf_addstr(&buf, filename);
+	}
 
 #ifndef NO_PTHREADS
 	if (num_threads) {
@@ -378,31 +396,260 @@ static void run_pager(struct grep_opt *opt, const char *prefix)
 		exit(status);
 }
 
-static int grep_cache(struct grep_opt *opt, const struct pathspec *pathspec, int cached)
+static void compile_submodule_options(const struct grep_opt *opt,
+				      const struct pathspec *pathspec,
+				      int cached, int untracked,
+				      int opt_exclude, int use_index,
+				      int pattern_type_arg)
+{
+	struct grep_pat *pattern;
+	int i;
+
+	if (recurse_submodules)
+		argv_array_push(&submodule_options, "--recurse-submodules");
+
+	if (cached)
+		argv_array_push(&submodule_options, "--cached");
+	if (!use_index)
+		argv_array_push(&submodule_options, "--no-index");
+	if (untracked)
+		argv_array_push(&submodule_options, "--untracked");
+	if (opt_exclude > 0)
+		argv_array_push(&submodule_options, "--exclude-standard");
+
+	if (opt->invert)
+		argv_array_push(&submodule_options, "-v");
+	if (opt->ignore_case)
+		argv_array_push(&submodule_options, "-i");
+	if (opt->word_regexp)
+		argv_array_push(&submodule_options, "-w");
+	switch (opt->binary) {
+	case GREP_BINARY_NOMATCH:
+		argv_array_push(&submodule_options, "-I");
+		break;
+	case GREP_BINARY_TEXT:
+		argv_array_push(&submodule_options, "-a");
+		break;
+	default:
+		break;
+	}
+	if (opt->allow_textconv)
+		argv_array_push(&submodule_options, "--textconv");
+	if (opt->max_depth != -1)
+		argv_array_pushf(&submodule_options, "--max-depth=%d",
+				 opt->max_depth);
+	if (opt->linenum)
+		argv_array_push(&submodule_options, "-n");
+	if (!opt->pathname)
+		argv_array_push(&submodule_options, "-h");
+	if (!opt->relative)
+		argv_array_push(&submodule_options, "--full-name");
+	if (opt->name_only)
+		argv_array_push(&submodule_options, "-l");
+	if (opt->unmatch_name_only)
+		argv_array_push(&submodule_options, "-L");
+	if (opt->null_following_name)
+		argv_array_push(&submodule_options, "-z");
+	if (opt->count)
+		argv_array_push(&submodule_options, "-c");
+	if (opt->file_break)
+		argv_array_push(&submodule_options, "--break");
+	if (opt->heading)
+		argv_array_push(&submodule_options, "--heading");
+	if (opt->pre_context)
+		argv_array_pushf(&submodule_options, "--before-context=%d",
+				 opt->pre_context);
+	if (opt->post_context)
+		argv_array_pushf(&submodule_options, "--after-context=%d",
+				 opt->post_context);
+	if (opt->funcname)
+		argv_array_push(&submodule_options, "-p");
+	if (opt->funcbody)
+		argv_array_push(&submodule_options, "-W");
+	if (opt->all_match)
+		argv_array_push(&submodule_options, "--all-match");
+	if (opt->debug)
+		argv_array_push(&submodule_options, "--debug");
+	if (opt->status_only)
+		argv_array_push(&submodule_options, "-q");
+
+	switch (pattern_type_arg) {
+	case GREP_PATTERN_TYPE_BRE:
+		argv_array_push(&submodule_options, "-G");
+		break;
+	case GREP_PATTERN_TYPE_ERE:
+		argv_array_push(&submodule_options, "-E");
+		break;
+	case GREP_PATTERN_TYPE_FIXED:
+		argv_array_push(&submodule_options, "-F");
+		break;
+	case GREP_PATTERN_TYPE_PCRE:
+		argv_array_push(&submodule_options, "-P");
+		break;
+	case GREP_PATTERN_TYPE_UNSPECIFIED:
+		break;
+	}
+
+	for (pattern = opt->pattern_list; pattern != NULL;
+	     pattern = pattern->next) {
+		switch (pattern->token) {
+		case GREP_PATTERN:
+			argv_array_pushf(&submodule_options, "-e%s",
+					 pattern->pattern);
+			break;
+		case GREP_AND:
+		case GREP_OPEN_PAREN:
+		case GREP_CLOSE_PAREN:
+		case GREP_NOT:
+		case GREP_OR:
+			argv_array_push(&submodule_options, pattern->pattern);
+			break;
+		/* BODY and HEAD are not used by git-grep */
+		case GREP_PATTERN_BODY:
+		case GREP_PATTERN_HEAD:
+			break;
+		}
+	}
+
+	/*
+	 * Limit number of threads for child process to use.
+	 * This is to prevent potential fork-bomb behavior of git-grep as each
+	 * submodule process has its own thread pool.
+	 */
+	argv_array_pushf(&submodule_options, "--threads=%d",
+			 (num_threads + 1) / 2);
+
+	/* Add Pathspecs */
+	argv_array_push(&submodule_options, "--");
+	for (i = 0; i < pathspec->nr; i++)
+		argv_array_push(&submodule_options,
+				pathspec->items[i].original);
+}
+
+/*
+ * Launch child process to grep contents of a submodule
+ */
+static int grep_submodule_launch(struct grep_opt *opt,
+				 const struct grep_source *gs)
+{
+	struct child_process cp = CHILD_PROCESS_INIT;
+	int status, i;
+	struct work_item *w = opt->output_priv;
+
+	prepare_submodule_repo_env(&cp.env_array);
+
+	/* Add super prefix */
+	argv_array_pushf(&cp.args, "--super-prefix=%s%s/",
+			 super_prefix ? super_prefix : "",
+			 gs->name);
+	argv_array_push(&cp.args, "grep");
+
+	/* Add options */
+	for (i = 0; i < submodule_options.argc; i++)
+		argv_array_push(&cp.args, submodule_options.argv[i]);
+
+	cp.git_cmd = 1;
+	cp.dir = gs->path;
+
+	/*
+	 * Capture output to output buffer and check the return code from the
+	 * child process.  A '0' indicates a hit, a '1' indicates no hit and
+	 * anything else is an error.
+	 */
+	status = capture_command(&cp, &w->out, 0);
+	if (status && (status != 1)) {
+		/* flush the buffer */
+		write_or_die(1, w->out.buf, w->out.len);
+		die("process for submodule '%s' failed with exit code: %d",
+		    gs->name, status);
+	}
+
+	/* invert the return code to make a hit equal to 1 */
+	return !status;
+}
+
+/*
+ * Prep grep structures for a submodule grep
+ * sha1: the sha1 of the submodule or NULL if using the working tree
+ * filename: name of the submodule including tree name of parent
+ * path: location of the submodule
+ */
+static int grep_submodule(struct grep_opt *opt, const unsigned char *sha1,
+			  const char *filename, const char *path)
+{
+	if (!is_submodule_initialized(path))
+		return 0;
+	if (!is_submodule_populated(path))
+		return 0;
+
+#ifndef NO_PTHREADS
+	if (num_threads) {
+		add_work(opt, GREP_SOURCE_SUBMODULE, filename, path, sha1);
+		return 0;
+	} else
+#endif
+	{
+		struct work_item w;
+		int hit;
+
+		grep_source_init(&w.source, GREP_SOURCE_SUBMODULE,
+				 filename, path, sha1);
+		strbuf_init(&w.out, 0);
+		opt->output_priv = &w;
+		hit = grep_submodule_launch(opt, &w.source);
+
+		write_or_die(1, w.out.buf, w.out.len);
+
+		grep_source_clear(&w.source);
+		strbuf_release(&w.out);
+		return hit;
+	}
+}
+
+static int grep_cache(struct grep_opt *opt, const struct pathspec *pathspec,
+		      int cached)
 {
 	int hit = 0;
 	int nr;
+	struct strbuf name = STRBUF_INIT;
+	int name_base_len = 0;
+	if (super_prefix) {
+		name_base_len = strlen(super_prefix);
+		strbuf_addstr(&name, super_prefix);
+	}
+
 	read_cache();
 
 	for (nr = 0; nr < active_nr; nr++) {
 		const struct cache_entry *ce = active_cache[nr];
-		if (!S_ISREG(ce->ce_mode))
+		strbuf_setlen(&name, name_base_len);
+		strbuf_addstr(&name, ce->name);
+
+		if (S_ISREG(ce->ce_mode) &&
+		    match_pathspec(pathspec, name.buf, name.len, 0, NULL,
+				   S_ISDIR(ce->ce_mode) ||
+				   S_ISGITLINK(ce->ce_mode))) {
+			/*
+			 * If CE_VALID is on, we assume worktree file and its
+			 * cache entry are identical, even if worktree file has
+			 * been modified, so use cache version instead
+			 */
+			if (cached || (ce->ce_flags & CE_VALID) ||
+			    ce_skip_worktree(ce)) {
+				if (ce_stage(ce) || ce_intent_to_add(ce))
+					continue;
+				hit |= grep_sha1(opt, ce->oid.hash, ce->name,
+						 0, ce->name);
+			} else {
+				hit |= grep_file(opt, ce->name);
+			}
+		} else if (recurse_submodules && S_ISGITLINK(ce->ce_mode) &&
+			   submodule_path_match(pathspec, name.buf, NULL)) {
+			hit |= grep_submodule(opt, NULL, ce->name, ce->name);
+		} else {
 			continue;
-		if (!ce_path_match(ce, pathspec, NULL))
-			continue;
-		/*
-		 * If CE_VALID is on, we assume worktree file and its cache entry
-		 * are identical, even if worktree file has been modified, so use
-		 * cache version instead
-		 */
-		if (cached || (ce->ce_flags & CE_VALID) || ce_skip_worktree(ce)) {
-			if (ce_stage(ce) || ce_intent_to_add(ce))
-				continue;
-			hit |= grep_sha1(opt, ce->oid.hash, ce->name, 0,
-					 ce->name);
 		}
-		else
-			hit |= grep_file(opt, ce->name);
+
 		if (ce_stage(ce)) {
 			do {
 				nr++;
@@ -413,6 +660,8 @@ static int grep_cache(struct grep_opt *opt, const struct pathspec *pathspec, int
 		if (hit && opt->status_only)
 			break;
 	}
+
+	strbuf_release(&name);
 	return hit;
 }
 
@@ -651,6 +900,8 @@ int cmd_grep(int argc, const char **argv, const char *prefix)
 			N_("search in both tracked and untracked files")),
 		OPT_SET_INT(0, "exclude-standard", &opt_exclude,
 			    N_("ignore files specified via '.gitignore'"), 1),
+		OPT_BOOL(0, "recurse-submodules", &recurse_submodules,
+			 N_("recursivley search in each submodule")),
 		OPT_GROUP(""),
 		OPT_BOOL('v', "invert-match", &opt.invert,
 			N_("show non-matching lines")),
@@ -755,6 +1006,7 @@ int cmd_grep(int argc, const char **argv, const char *prefix)
 	init_grep_defaults();
 	git_config(grep_cmd_config, NULL);
 	grep_init(&opt, prefix);
+	super_prefix = get_super_prefix();
 
 	/*
 	 * If there is no -- then the paths must exist in the working
@@ -872,6 +1124,13 @@ int cmd_grep(int argc, const char **argv, const char *prefix)
 	pathspec.max_depth = opt.max_depth;
 	pathspec.recursive = 1;
 
+	if (recurse_submodules) {
+		gitmodules_config();
+		compile_submodule_options(&opt, &pathspec, cached, untracked,
+					  opt_exclude, use_index,
+					  pattern_type_arg);
+	}
+
 	if (show_in_pager && (cached || list.nr))
 		die(_("--open-files-in-pager only works on the worktree"));
 
@@ -895,6 +1154,9 @@ int cmd_grep(int argc, const char **argv, const char *prefix)
 		}
 	}
 
+	if (recurse_submodules && (!use_index || untracked || list.nr))
+		die(_("option not supported with --recurse-submodules."));
+
 	if (!show_in_pager && !opt.status_only)
 		setup_pager();
 
diff --git a/git.c b/git.c
index dce529fcbf..c95d3e30da 100644
--- a/git.c
+++ b/git.c
@@ -434,7 +434,7 @@ static struct cmd_struct commands[] = {
 	{ "fsck-objects", cmd_fsck, RUN_SETUP },
 	{ "gc", cmd_gc, RUN_SETUP },
 	{ "get-tar-commit-id", cmd_get_tar_commit_id },
-	{ "grep", cmd_grep, RUN_SETUP_GENTLY },
+	{ "grep", cmd_grep, RUN_SETUP_GENTLY | SUPPORT_SUPER_PREFIX },
 	{ "hash-object", cmd_hash_object },
 	{ "help", cmd_help },
 	{ "index-pack", cmd_index_pack, RUN_SETUP_GENTLY },
diff --git a/t/t7814-grep-recurse-submodules.sh b/t/t7814-grep-recurse-submodules.sh
new file mode 100755
index 0000000000..1019125e52
--- /dev/null
+++ b/t/t7814-grep-recurse-submodules.sh
@@ -0,0 +1,99 @@
+#!/bin/sh
+
+test_description='Test grep recurse-submodules feature
+
+This test verifies the recurse-submodules feature correctly greps across
+submodules.
+'
+
+. ./test-lib.sh
+
+test_expect_success 'setup directory structure and submodule' '
+	echo "foobar" >a &&
+	mkdir b &&
+	echo "bar" >b/b &&
+	git add a b &&
+	git commit -m "add a and b" &&
+	git init submodule &&
+	echo "foobar" >submodule/a &&
+	git -C submodule add a &&
+	git -C submodule commit -m "add a" &&
+	git submodule add ./submodule &&
+	git commit -m "added submodule"
+'
+
+test_expect_success 'grep correctly finds patterns in a submodule' '
+	cat >expect <<-\EOF &&
+	a:foobar
+	b/b:bar
+	submodule/a:foobar
+	EOF
+
+	git grep -e "bar" --recurse-submodules >actual &&
+	test_cmp expect actual
+'
+
+test_expect_success 'grep and basic pathspecs' '
+	cat >expect <<-\EOF &&
+	submodule/a:foobar
+	EOF
+
+	git grep -e. --recurse-submodules -- submodule >actual &&
+	test_cmp expect actual
+'
+
+test_expect_success 'grep and nested submodules' '
+	git init submodule/sub &&
+	echo "foobar" >submodule/sub/a &&
+	git -C submodule/sub add a &&
+	git -C submodule/sub commit -m "add a" &&
+	git -C submodule submodule add ./sub &&
+	git -C submodule add sub &&
+	git -C submodule commit -m "added sub" &&
+	git add submodule &&
+	git commit -m "updated submodule" &&
+
+	cat >expect <<-\EOF &&
+	a:foobar
+	b/b:bar
+	submodule/a:foobar
+	submodule/sub/a:foobar
+	EOF
+
+	git grep -e "bar" --recurse-submodules >actual &&
+	test_cmp expect actual
+'
+
+test_expect_success 'grep and multiple patterns' '
+	cat >expect <<-\EOF &&
+	a:foobar
+	submodule/a:foobar
+	submodule/sub/a:foobar
+	EOF
+
+	git grep -e "bar" --and -e "foo" --recurse-submodules >actual &&
+	test_cmp expect actual
+'
+
+test_expect_success 'grep and multiple patterns' '
+	cat >expect <<-\EOF &&
+	b/b:bar
+	EOF
+
+	git grep -e "bar" --and --not -e "foo" --recurse-submodules >actual &&
+	test_cmp expect actual
+'
+
+test_incompatible_with_recurse_submodules ()
+{
+	test_expect_success "--recurse-submodules and $1 are incompatible" "
+		test_must_fail git grep -e. --recurse-submodules $1 2>actual &&
+		test_i18ngrep 'not supported with --recurse-submodules' actual
+	"
+}
+
+test_incompatible_with_recurse_submodules --untracked
+test_incompatible_with_recurse_submodules --no-index
+test_incompatible_with_recurse_submodules HEAD
+
+test_done