diff --git a/BRANCHES.md b/BRANCHES.md
index 680c0cabc0fa..6d2e5c0e4e12 100644
--- a/BRANCHES.md
+++ b/BRANCHES.md
@@ -16,6 +16,11 @@ API compatibility in the `master` branch between major version changes. We
 also maintain ABI compatibility within LTS branches; see the next section for
 details.
 
+Every major version will become an LTS branch when the next major version is
+released. We may occasionally create LTS branches from other releases at our
+discretion.
+When a new LTS branch is created, it usually remains supported for three years.
+
 ## Backwards Compatibility for application code
 
 We maintain API compatibility in released versions of Mbed TLS. If you have