diff --git a/Documentation/git-add.adoc b/Documentation/git-add.adoc
index 6192daeb0371cf..c864ce272dd95d 100644
--- a/Documentation/git-add.adoc
+++ b/Documentation/git-add.adoc
@@ -10,7 +10,7 @@ SYNOPSIS
 [synopsis]
 git add [--verbose | -v] [--dry-run | -n] [--force | -f] [--interactive | -i] [--patch | -p]
 	[--edit | -e] [--[no-]all | -A | --[no-]ignore-removal | [--update | -u]] [--sparse]
-	[--intent-to-add | -N] [--refresh] [--ignore-errors] [--ignore-missing] [--renormalize]
+	[--intent-to-add | -N] [--refresh] [--ignore-errors] [--ignore-missing] [--renormalize] [--no-verify]
 	[--chmod=(+|-)x] [--pathspec-from-file=<file> [--pathspec-file-nul]]
 	[--] [<pathspec>...]
 
@@ -42,6 +42,10 @@ use the `--force` option to add ignored files. If you specify the exact
 filename of an ignored file, `git add` will fail with a list of ignored
 files. Otherwise it will silently ignore the file.
 
+A pre-add hook can be run to inspect or reject the proposed index update
+after `git add` computes staging and writes it to the index lockfile,
+but before writing it to the final index. See linkgit:githooks[5].
+
 Please see linkgit:git-commit[1] for alternative ways to add content to a
 commit.
 
@@ -163,6 +167,10 @@ for `git add --no-all <pathspec>...`, i.e. ignored removed files.
 	Don't add the file(s), but only refresh their stat()
 	information in the index.
 
+`--no-verify`::
+	Bypass the pre-add hook if it exists. See linkgit:githooks[5] for
+	more information about hooks.
+
 `--ignore-errors`::
 	If some files could not be added because of errors indexing
 	them, do not abort the operation, but continue adding the
@@ -451,6 +459,7 @@ linkgit:git-reset[1]
 linkgit:git-mv[1]
 linkgit:git-commit[1]
 linkgit:git-update-index[1]
+linkgit:githooks[5]
 
 GIT
 ---
diff --git a/Documentation/githooks.adoc b/Documentation/githooks.adoc
index 056553788d4f43..7ef8718112a733 100644
--- a/Documentation/githooks.adoc
+++ b/Documentation/githooks.adoc
@@ -94,6 +94,33 @@ and is invoked after the patch is applied and a commit is made.
 This hook is meant primarily for notification, and cannot affect
 the outcome of `git am`.
 
+pre-add
+~~~~~~~
+
+This hook is invoked by linkgit:git-add[1], and can be bypassed with the
+`--no-verify` option. It is not invoked for `--interactive`, `--patch`,
+`--edit`, or `--dry-run`.
+
+It takes two parameters: the path to a copy of the index before this
+invocation of `git add`, and the path to the lockfile containing the
+proposed index after staging. It does not read from standard input.
+If no index exists yet, the first parameter names a path that does not
+exist and should be treated as an empty index. No special environment
+variables are set. The hook is invoked after the index has been updated
+in memory and written to the lockfile, but before it is committed to the
+final location.
+
+Exiting with a non-zero status causes `git add` to abort and leaves the
+index unchanged. Exiting with zero status causes the staged changes to
+take effect.
+
+This hook can be used to prevent staging of files based on names, content,
+or sizes (e.g., to block `.env` files, secret keys, or large files).
+
+This hook is not invoked by `git commit -a` or `git commit --include`
+which still can run the pre-commit hook, providing a control point at
+commit time.
+
 pre-commit
 ~~~~~~~~~~
 
diff --git a/builtin/add.c b/builtin/add.c
index 32709794b3873f..735c9a53fdffc4 100644
--- a/builtin/add.c
+++ b/builtin/add.c
@@ -25,6 +25,8 @@
 #include "strvec.h"
 #include "submodule.h"
 #include "add-interactive.h"
+#include "hook.h"
+#include "copy.h"
 
 static const char * const builtin_add_usage[] = {
 	N_("git add [<options>] [--] <pathspec>..."),
@@ -36,6 +38,7 @@ static int take_worktree_changes;
 static int add_renormalize;
 static int pathspec_file_nul;
 static int include_sparse;
+static int no_verify;
 static const char *pathspec_from_file;
 
 static int chmod_pathspec(struct repository *repo,
@@ -271,6 +274,7 @@ static struct option builtin_add_options[] = {
 	OPT_BOOL( 0 , "refresh", &refresh_only, N_("don't add, only refresh the index")),
 	OPT_BOOL( 0 , "ignore-errors", &ignore_add_errors, N_("just skip files which cannot be added because of errors")),
 	OPT_BOOL( 0 , "ignore-missing", &ignore_missing, N_("check if - even missing - files are ignored in dry run")),
+	OPT_BOOL( 0 , "no-verify", &no_verify, N_("bypass pre-add hook")),
 	OPT_BOOL(0, "sparse", &include_sparse, N_("allow updating entries outside of the sparse-checkout cone")),
 	OPT_STRING(0, "chmod", &chmod_arg, "(+|-)x",
 		   N_("override the executable bit of the listed files")),
@@ -391,6 +395,9 @@ int cmd_add(int argc,
 	char *ps_matched = NULL;
 	struct lock_file lock_file = LOCK_INIT;
 	struct odb_transaction *transaction;
+	int run_pre_add = 0;
+	struct tempfile *orig_index = NULL;
+	char *orig_index_path = NULL;
 
 	repo_config(repo, add_config, NULL);
 
@@ -576,6 +583,34 @@ int cmd_add(int argc,
 		string_list_clear(&only_match_skip_worktree, 0);
 	}
 
+	if (!show_only && !no_verify && find_hook(repo, "pre-add")) {
+		int fd_in, status;
+		const char *index_file = repo_get_index_file(repo);
+		char *template;
+
+		run_pre_add = 1;
+		template = xstrfmt("%s.pre-add.XXXXXX", index_file);
+		orig_index = xmks_tempfile(template);
+		free(template);
+
+		fd_in = open(index_file, O_RDONLY);
+		if (fd_in >= 0) {
+			status = copy_fd(fd_in, get_tempfile_fd(orig_index));
+			if (close(fd_in))
+				die_errno(_("unable to close index for pre-add hook"));
+			if (close_tempfile_gently(orig_index))
+				die_errno(_("unable to close temporary index copy"));
+			if (status < 0)
+				die(_("failed to copy index for pre-add hook"));
+		} else if (errno == ENOENT) {
+			orig_index_path = xstrdup(get_tempfile_path(orig_index));
+			if (delete_tempfile(&orig_index))
+				die_errno(_("unable to remove temporary index copy"));
+		} else {
+			die_errno(_("unable to open index for pre-add hook"));
+		}
+	}
+
 	transaction = odb_transaction_begin(repo->objects);
 
 	ps_matched = xcalloc(pathspec.nr, 1);
@@ -587,8 +622,12 @@ int cmd_add(int argc,
 						  include_sparse, flags);
 
 	if (take_worktree_changes && !add_renormalize && !ignore_add_errors &&
-	    report_path_error(ps_matched, &pathspec))
+	    report_path_error(ps_matched, &pathspec)) {
+		if (orig_index)
+			delete_tempfile(&orig_index);
+		free(orig_index_path);
 		exit(128);
+	}
 
 	if (add_new_files)
 		exit_status |= add_files(repo, &dir, flags);
@@ -598,9 +637,30 @@ int cmd_add(int argc,
 	odb_transaction_commit(transaction);
 
 finish:
-	if (write_locked_index(repo->index, &lock_file,
-			       COMMIT_LOCK | SKIP_IF_UNCHANGED))
-		die(_("unable to write new index file"));
+	if (run_pre_add && !exit_status && repo->index->cache_changed) {
+		struct run_hooks_opt opt = RUN_HOOKS_OPT_INIT;
+
+		if (write_locked_index(repo->index, &lock_file, 0))
+			die(_("unable to write new index file"));
+
+		strvec_push(&opt.args, orig_index ? get_tempfile_path(orig_index) :
+					     orig_index_path);
+		strvec_push(&opt.args, get_lock_file_path(&lock_file));
+		if (run_hooks_opt(repo, "pre-add", &opt)) {
+			rollback_lock_file(&lock_file); /* hook rejected */
+			exit_status = 1;
+		} else {
+			if (commit_lock_file(&lock_file)) /* hook approved */
+				die(_("unable to write new index file"));
+		}
+	} else {
+		if (write_locked_index(repo->index, &lock_file,
+				       COMMIT_LOCK | SKIP_IF_UNCHANGED))
+			die(_("unable to write new index file"));
+	}
+
+	delete_tempfile(&orig_index);
+	free(orig_index_path);
 
 	free(ps_matched);
 	dir_clear(&dir);
diff --git a/t/meson.build b/t/meson.build
index 459c52a48972e4..d518596fcbb0ac 100644
--- a/t/meson.build
+++ b/t/meson.build
@@ -412,6 +412,7 @@ integration_tests = [
   't3703-add-magic-pathspec.sh',
   't3704-add-pathspec-file.sh',
   't3705-add-sparse-checkout.sh',
+  't3706-pre-add-hook.sh',
   't3800-mktag.sh',
   't3900-i18n-commit.sh',
   't3901-i18n-patch.sh',
diff --git a/t/t3706-pre-add-hook.sh b/t/t3706-pre-add-hook.sh
new file mode 100755
index 00000000000000..5ff7161f9d84b6
--- /dev/null
+++ b/t/t3706-pre-add-hook.sh
@@ -0,0 +1,227 @@
+#!/bin/sh
+
+test_description='pre-add hook tests
+
+These tests run git add with and without pre-add hooks to ensure functionality. Largely derived from t7503 (pre-commit and pre-merge-commit hooks) and t5571 (pre-push hooks).'
+
+GIT_TEST_DEFAULT_INITIAL_BRANCH_NAME=main
+export GIT_TEST_DEFAULT_INITIAL_BRANCH_NAME
+
+. ./test-lib.sh
+
+test_expect_success 'with no hook' '
+	test_when_finished "rm -f actual" &&
+	echo content >file &&
+	git add file &&
+	test_path_is_missing actual
+'
+
+test_expect_success POSIXPERM 'with non-executable hook' '
+	test_when_finished "rm -f actual" &&
+	test_hook pre-add <<-\EOF &&
+	echo should-not-run >>actual
+	exit 1
+	EOF
+	chmod -x .git/hooks/pre-add &&
+
+	echo content >file &&
+	git add file &&
+	test_path_is_missing actual
+'
+
+test_expect_success '--no-verify with no hook' '
+	echo content >file &&
+	git add --no-verify file &&
+	test_path_is_missing actual
+'
+
+test_expect_success 'with succeeding hook' '
+	test_when_finished "rm -f actual expected" &&
+	echo "pre-add" >expected &&
+	test_hook pre-add <<-\EOF &&
+	echo pre-add >>actual
+	EOF
+
+	echo content >file &&
+	git add file &&
+	test_cmp expected actual
+'
+
+test_expect_success 'with failing hook' '
+	test_when_finished "rm -f actual" &&
+	test_hook pre-add <<-\EOF &&
+	echo pre-add-rejected >>actual
+	exit 1
+	EOF
+
+	echo content >file &&
+	test_must_fail git add file
+'
+
+test_expect_success '--no-verify with failing hook' '
+	test_when_finished "rm -f actual" &&
+	test_hook pre-add <<-\EOF &&
+	echo should-not-run >>actual
+	exit 1
+	EOF
+
+	echo content >file &&
+	git add --no-verify file &&
+	test_path_is_missing actual
+'
+
+test_expect_success 'hook receives original and proposed index as arguments' '
+	test_when_finished "rm -f tracked expected hook-ran" &&
+	echo "initial" >tracked &&
+	git add tracked &&
+	git commit -m "initial" &&
+	test_hook pre-add <<-\EOF &&
+	test $# -eq 2 &&
+	test -f "$1" &&
+	test -f "$2" &&
+	echo pass >hook-ran
+	EOF
+
+	echo "modified" >tracked &&
+	git add tracked &&
+	echo pass >expected &&
+	test_cmp expected hook-ran
+'
+
+test_expect_success 'hook handles first add with no existing index' '
+	test_when_finished "rm -rf no-index" &&
+	test_create_repo no-index &&
+	echo ok >no-index/expected &&
+	test_hook -C no-index pre-add <<-\EOF &&
+	test $# -eq 2 &&
+	test ! -e "$1" &&
+	test -f "$2" &&
+	echo ok >hook-ran
+	EOF
+
+	echo first >no-index/file &&
+	git -C no-index add file &&
+	test_cmp no-index/expected no-index/hook-ran
+'
+
+test_expect_success 'hook is not invoked with --dry-run (show-only)' '
+	test_when_finished "rm -f actual" &&
+	test_hook pre-add <<-\EOF &&
+	echo should-not-run >>actual
+	exit 1
+	EOF
+
+	echo content >file &&
+	git add --dry-run file &&
+	test_path_is_missing actual
+'
+
+test_expect_success 'hook is invoked with git add -u' '
+	test_when_finished "rm -f actual expected file" &&
+	echo "initial" >file &&
+	git add file &&
+	git commit -m "initial" &&
+	echo "pre-add" >expected &&
+	test_hook pre-add <<-\EOF &&
+	echo pre-add >>actual
+	EOF
+
+	echo modified >file &&
+	git add -u &&
+	test_cmp expected actual
+'
+
+test_expect_success 'hook can compare original and proposed index' '
+	test_when_finished "rm -f old-raw new-raw old-list new-list \
+			    expected-old expected-new" &&
+	echo "initial" >file1 &&
+	echo "initial" >file2 &&
+	git add file1 file2 &&
+	git commit -m "initial" &&
+	echo "staged-before" >file1 &&
+	git add file1 &&
+	test_hook pre-add <<-\EOF &&
+	GIT_INDEX_FILE="$1" git diff --cached --name-only HEAD >old-raw &&
+	GIT_INDEX_FILE="$2" git diff --cached --name-only HEAD >new-raw &&
+	sort old-raw >old-list &&
+	sort new-raw >new-list
+	EOF
+
+	echo "modified" >file2 &&
+	git add file2 &&
+	echo file1 >expected-old &&
+	printf "%s\n" file1 file2 >expected-new &&
+	test_cmp expected-old old-list &&
+	test_cmp expected-new new-list
+'
+
+test_expect_success 'hook rejection rolls back index unchanged' '
+	test_when_finished "rm -f file before after old-raw new-raw \
+			    old-list new-list expected-old expected-new" &&
+	echo "initial" >file &&
+	git add file &&
+	git commit -m "initial" &&
+	git diff --cached --name-only HEAD >before &&
+	test_hook pre-add <<-\EOF &&
+	GIT_INDEX_FILE="$1" git diff --cached --name-only HEAD >old-raw &&
+	GIT_INDEX_FILE="$2" git diff --cached --name-only HEAD >new-raw &&
+	sort old-raw >old-list &&
+	sort new-raw >new-list &&
+	exit 1
+	EOF
+
+	echo "modified" >file &&
+	test_must_fail git add file &&
+	git diff --cached --name-only HEAD >after &&
+	test_cmp before after &&
+	: >expected-old &&
+	echo file >expected-new &&
+	test_cmp expected-old old-list &&
+	test_cmp expected-new new-list
+'
+
+test_expect_success 'hook example: block .env files' '
+	test_when_finished "rm -f .env safe.txt new-paths" &&
+	echo "initial" >base &&
+	git add base &&
+	git commit -m "initial" &&
+	test_hook pre-add <<-\EOF &&
+	GIT_INDEX_FILE="$2" git diff --cached --name-only HEAD >new-paths &&
+	while read path
+	do
+		case "$path" in
+		*.env|.env)
+			echo "error: $path must not be staged" >&2
+			exit 1
+			;;
+		esac
+	done <new-paths
+	EOF
+
+	echo "DB_PASS=secret" >.env &&
+	test_must_fail git add .env &&
+	echo "safe content" >safe.txt &&
+	git add safe.txt
+'
+
+test_expect_success 'hook example: block secrets in content' '
+	test_when_finished "rm -f config.txt secret" &&
+	echo "initial" >config.txt &&
+	git add config.txt &&
+	git commit -m "initial" &&
+	test_hook pre-add <<-\EOF &&
+	GIT_INDEX_FILE="$2" git diff --cached HEAD >secret &&
+	if grep -qE "(API_KEY|SECRET_KEY|PRIVATE_KEY)=" secret
+	then
+		echo "error: staged content contains secrets" >&2
+		exit 1
+	fi
+	EOF
+
+	echo "API_KEY=sksksk-live-12345" >config.txt &&
+	test_must_fail git add config.txt &&
+	echo "LOG_LEVEL=debug" >config.txt &&
+	git add config.txt
+'
+
+test_done