diff --git a/.changelog/unreleased/improvements/1428-finalizeblock-deserialization.md b/.changelog/unreleased/improvements/1428-finalizeblock-deserialization.md
new file mode 100644
index 000000000..cc9ca040f
--- /dev/null
+++ b/.changelog/unreleased/improvements/1428-finalizeblock-deserialization.md
@@ -0,0 +1 @@
+- `[tendermint]` Fix `FinalizeBlock::validator_updates` deserialization as `nullable` ([\#1428](https://github.com/informalsystems/tendermint-rs/pull/1428))
diff --git a/tendermint/src/abci/response/finalize_block.rs b/tendermint/src/abci/response/finalize_block.rs
index 124ce1aca..0cc2c8128 100644
--- a/tendermint/src/abci/response/finalize_block.rs
+++ b/tendermint/src/abci/response/finalize_block.rs
@@ -16,6 +16,7 @@ pub struct FinalizeBlock {
     pub tx_results: Vec<ExecTxResult>,
     /// A list of updates to the validator set.
     /// These will reflect the validator set at current height + 2.
+    #[serde(with = "serializers::nullable")]
     pub validator_updates: Vec<validator::Update>,
     /// Updates to the consensus params, if any.
     #[serde(default)]