diff --git a/t/t5608-clone-2gb.sh b/t/t5608-clone-2gb.sh
index 87a8cd9f98..af93302dde 100755
--- a/t/t5608-clone-2gb.sh
+++ b/t/t5608-clone-2gb.sh
@@ -49,4 +49,41 @@ test_expect_success 'clone - with worktree, file:// protocol' '
 
 '
 
+test_expect_success SIZE_T_IS_64BIT 'set up repo with >4GB object' '
+	large_blob_size=$((4*1024*1024*1024+1)) &&
+	git init --bare 4gb-repo &&
+	head_oid=$(test-tool synthesize pack \
+		--reachable-large "$large_blob_size" \
+		4gb-repo/objects/pack/test.pack) &&
+	git -C 4gb-repo index-pack objects/pack/test.pack &&
+	git -C 4gb-repo update-ref refs/heads/main $head_oid &&
+	git -C 4gb-repo symbolic-ref HEAD refs/heads/main
+'
+
+test_expect_success SIZE_T_IS_64BIT 'clone >4GB object via unpack-objects' '
+	# The synthesized pack has five objects, so a large unpack limit keeps
+	# fetch-pack on the unpack-objects path.
+	git -c fetch.unpackLimit=100 clone --bare \
+		"file://$(pwd)/4gb-repo" 4gb-clone-unpack &&
+
+	# Verify the large blob survived the clone by comparing its OID
+	# between source and clone.  We cannot use "cat-file -s" because
+	# object_info.sizep is still unsigned long, which truncates >4GB
+	# sizes on Windows.  OID equality proves content integrity since
+	# the clone already verified checksums via index-pack/unpack-objects.
+	source_blob=$(git -C 4gb-repo rev-parse main^:file) &&
+	clone_blob=$(git -C 4gb-clone-unpack rev-parse main^:file) &&
+	test "$source_blob" = "$clone_blob"
+'
+
+test_expect_success SIZE_T_IS_64BIT 'clone with >4GB object via index-pack' '
+	# Force fetch-pack to hand the pack to index-pack instead.
+	git -c fetch.unpackLimit=1 clone --bare \
+		"file://$(pwd)/4gb-repo" 4gb-clone-index &&
+
+	source_blob=$(git -C 4gb-repo rev-parse main^:file) &&
+	clone_blob=$(git -C 4gb-clone-index rev-parse main^:file) &&
+	test "$source_blob" = "$clone_blob"
+'
+
 test_done