diff --git a/.changelog/unreleased/breaking-changes/246-tendermint-proto-0-40-0.md b/.changelog/unreleased/breaking-changes/246-tendermint-proto-0-40-0.md
new file mode 100644
index 0000000..d5daf82
--- /dev/null
+++ b/.changelog/unreleased/breaking-changes/246-tendermint-proto-0-40-0.md
@@ -0,0 +1,2 @@
+- Update `tendermint-proto` to `v0.40.0`
+  ([\#246](https://github.com/cosmos/ibc-proto-rs/issues/246))
\ No newline at end of file
diff --git a/Cargo.toml b/Cargo.toml
index 57f2218..fb46989 100644
--- a/Cargo.toml
+++ b/Cargo.toml
@@ -40,7 +40,7 @@ ics23                  = { version = "0.12.0", default-features = false }
 informalsystems-pbjson = { version = "0.7.0", optional = true, default-features = false }
 
 [dependencies.tendermint-proto]
-version          = "0.39"
+version          = "0.40.0"
 default-features = false
 
 [dependencies.cosmos-sdk-proto]