diff --git a/org.eclipse.jgit.test/tst/org/eclipse/jgit/internal/storage/file/GcOrphanFilesTest.java b/org.eclipse.jgit.test/tst/org/eclipse/jgit/internal/storage/file/GcOrphanFilesTest.java
index 79d72c5..e54c4ad 100644
--- a/org.eclipse.jgit.test/tst/org/eclipse/jgit/internal/storage/file/GcOrphanFilesTest.java
+++ b/org.eclipse.jgit.test/tst/org/eclipse/jgit/internal/storage/file/GcOrphanFilesTest.java
@@ -57,11 +57,15 @@
 
 	private final static String BITMAP_File_1 = PACK + "-1.bitmap";
 
-	private final static String IDX_File_2 = PACK + "-2.idx";
+	private static final String BITMAP_File_2 = PACK + "-2.bitmap";
+
+	private static final String IDX_File_2 = PACK + "-2.idx";
 
 	private final static String IDX_File_malformed = PACK + "-1234idx";
 
-	private final static String PACK_File_2 = PACK + "-2.pack";
+	private static final String KEEP_File_2 = PACK + "-2.keep";
+
+	private static final String PACK_File_2 = PACK + "-2.pack";
 
 	private final static String PACK_File_3 = PACK + "-3.pack";
 
@@ -105,6 +109,22 @@
 		assertTrue(new File(packDir, IDX_File_malformed).exists());
 	}
 
+	@Test
+	public void keepPreventsDeletionOfIndexFilesForMissingPackFile()
+			throws Exception {
+		createFileInPackFolder(BITMAP_File_1);
+		createFileInPackFolder(IDX_File_2);
+		createFileInPackFolder(BITMAP_File_2);
+		createFileInPackFolder(KEEP_File_2);
+		createFileInPackFolder(PACK_File_3);
+		gc.gc();
+		assertFalse(new File(packDir, BITMAP_File_1).exists());
+		assertTrue(new File(packDir, BITMAP_File_2).exists());
+		assertTrue(new File(packDir, IDX_File_2).exists());
+		assertTrue(new File(packDir, KEEP_File_2).exists());
+		assertTrue(new File(packDir, PACK_File_3).exists());
+	}
+
 	private void createFileInPackFolder(String fileName) throws IOException {
 		if (!packDir.exists() || !packDir.isDirectory()) {
 			assertTrue(packDir.mkdirs());
diff --git a/org.eclipse.jgit/src/org/eclipse/jgit/internal/storage/file/GC.java b/org.eclipse.jgit/src/org/eclipse/jgit/internal/storage/file/GC.java
index 791a108..25c5dcf 100644
--- a/org.eclipse.jgit/src/org/eclipse/jgit/internal/storage/file/GC.java
+++ b/org.eclipse.jgit/src/org/eclipse/jgit/internal/storage/file/GC.java
@@ -148,6 +148,8 @@
 
 	private static final String INDEX_EXT = "." + PackExt.INDEX.getExtension(); //$NON-NLS-1$
 
+	private static final String KEEP_EXT = "." + PackExt.KEEP.getExtension(); //$NON-NLS-1$
+
 	private static final int DEFAULT_AUTOPACKLIMIT = 50;
 
 	private static final int DEFAULT_AUTOLIMIT = 6700;
@@ -978,7 +980,10 @@
 			fileNames = files.map(path -> path.getFileName().toString())
 					.filter(name -> (name.endsWith(PACK_EXT)
 							|| name.endsWith(BITMAP_EXT)
-							|| name.endsWith(INDEX_EXT)))
+							|| name.endsWith(INDEX_EXT)
+							|| name.endsWith(KEEP_EXT)))
+					// sort files with same base name in the order:
+					// .pack, .keep, .index, .bitmap to avoid look ahead
 					.sorted(Collections.reverseOrder())
 					.collect(Collectors.toList());
 		} catch (IOException e1) {
@@ -990,7 +995,7 @@
 
 		String base = null;
 		for (String n : fileNames) {
-			if (n.endsWith(PACK_EXT)) {
+			if (n.endsWith(PACK_EXT) || n.endsWith(KEEP_EXT)) {
 				base = n.substring(0, n.lastIndexOf('.'));
 			} else {
 				if (base == null || !n.startsWith(base)) {