diff --git a/Documentation/config/index.txt b/Documentation/config/index.txt
index 8e138aba7a..de44183235 100644
--- a/Documentation/config/index.txt
+++ b/Documentation/config/index.txt
@@ -5,6 +5,13 @@ index.recordEndOfIndexEntries::
 	reading the index using Git versions before 2.20. Defaults to
 	'false'.
 
+index.recordOffsetTable::
+	Specifies whether the index file should include an "Index Entry
+	Offset Table" section. This reduces index load time on
+	multiprocessor machines but produces a message "ignoring IEOT
+	extension" when reading the index using Git versions before 2.20.
+	Defaults to 'false'.
+
 index.threads::
 	Specifies the number of threads to spawn when loading the index.
 	This is meant to reduce index load time on multiprocessor machines.
diff --git a/read-cache.c b/read-cache.c
index 1e9c772603..f3d5638d9e 100644
--- a/read-cache.c
+++ b/read-cache.c
@@ -2698,6 +2698,15 @@ static int record_eoie(void)
 	return 0;
 }
 
+static int record_ieot(void)
+{
+	int val;
+
+	if (!git_config_get_bool("index.recordoffsettable", &val))
+		return val;
+	return 0;
+}
+
 /*
  * On success, `tempfile` is closed. If it is the temporary file
  * of a `struct lock_file`, we will therefore effectively perform
@@ -2761,7 +2770,7 @@ static int do_write_index(struct index_state *istate, struct tempfile *tempfile,
 	else
 		nr_threads = 1;
 
-	if (nr_threads != 1) {
+	if (nr_threads != 1 && record_ieot()) {
 		int ieot_blocks, cpus;
 
 		/*