diff --git a/doc/xds-test-descriptions.md b/doc/xds-test-descriptions.md
index 06c1d50af54..721b1e7414c 100644
--- a/doc/xds-test-descriptions.md
+++ b/doc/xds-test-descriptions.md
@@ -296,3 +296,36 @@ Assert:
 1. Once all backends receive at least one RPC, the following 1000 RPCs are
 distributed across the 2 backends as a: 20, b: 80.
 
+### gentle_failover
+
+This test verifies that traffic is partially diverted to a secondary locality
+when > 50% of the instances in the primary locality are unhealthy.
+
+Client parameters:
+
+1.  --num_channels=1
+1.  --qps=100
+
+Load balancer configuration:
+
+1.  The primary MIG with 3 backends in the same zone as the client
+1.  The secondary MIG with 2 backends in a different zone
+
+Test driver asserts:
+
+1.  All backends in the primary locality receive at least 1 RPC.
+1.  No backends in the secondary locality receive RPCs.
+
+The test driver stops 2 of 3 backends in the primary locality.
+
+Test driver asserts:
+
+1.  All backends in the secondary locality receive at least 1 RPC.
+1.  The remaining backend in the primary locality receives at least 1 RPC.
+
+The test driver resumes the backends in the primary locality.
+
+Test driver asserts:
+
+1.  All backends in the primary locality receive at least 1 RPC.
+1.  No backends in the secondary locality receive RPCs.