diff --git a/CHANGELOG.md b/CHANGELOG.md
index ae235846..39be5e03 100644
--- a/CHANGELOG.md
+++ b/CHANGELOG.md
@@ -86,6 +86,7 @@ and this project adheres to
   `isMsgClearAdminEncodeObject` etc helpers.
 - @cosmjs/stargate: Add transfer queries codec, as well as transfer query
   methods to IBC query extension.
+- @cosmjs/tendermint-rpc: Export `ValidatorSecp256k1Pubkey` interface.
 
 ### Changed
 
@@ -152,6 +153,10 @@ and this project adheres to
   instead of a single `hdPath`. `DirectSecp256k1HdWallet.generate` now also
   accepts options via this interface. This adds support for multiple accounts
   from the same mnemonic to `DirectSecp256k1HdWallet`.
+- @cosmjs/tendermint-rpc: `ValidatorPubkey` is now a union of
+  `ValidatorEd25519Pubkey` and the newly exported `ValidatorSecp256k1Pubkey`
+  interface.
+- @cosmjs/tendermint-rpc: `decodePubkey` now supports secp256k1 public keys.
 
 ### Deprecated
 
diff --git a/packages/tendermint-rpc/src/index.ts b/packages/tendermint-rpc/src/index.ts
index 1bcb3e6a..5530c322 100644
--- a/packages/tendermint-rpc/src/index.ts
+++ b/packages/tendermint-rpc/src/index.ts
@@ -85,6 +85,12 @@ export {
   toSeconds,
 } from "./dates";
 export { HttpClient, WebsocketClient } from "./rpcclients"; // TODO: Why do we export those outside of this package?
-export { BlockIdFlag, CommitSignature, ValidatorEd25519Pubkey, ValidatorPubkey } from "./types";
+export {
+  BlockIdFlag,
+  CommitSignature,
+  ValidatorEd25519Pubkey,
+  ValidatorSecp256k1Pubkey,
+  ValidatorPubkey,
+} from "./types";
 export * as tendermint34 from "./tendermint34";
 export { Tendermint34Client } from "./tendermint34";
diff --git a/packages/tendermint-rpc/src/legacy/adaptors/v0-33/responses.ts b/packages/tendermint-rpc/src/legacy/adaptors/v0-33/responses.ts
index 9feb8c2e..381904e4 100644
--- a/packages/tendermint-rpc/src/legacy/adaptors/v0-33/responses.ts
+++ b/packages/tendermint-rpc/src/legacy/adaptors/v0-33/responses.ts
@@ -150,14 +150,21 @@ interface RpcPubkey {
 }
 
 function decodePubkey(data: RpcPubkey): ValidatorPubkey {
-  if (data.type === "tendermint/PubKeyEd25519") {
+  switch (data.type) {
     // go-amino special code
-    return {
-      algorithm: "ed25519",
-      data: fromBase64(assertNotEmpty(data.value)),
-    };
+    case "tendermint/PubKeyEd25519":
+      return {
+        algorithm: "ed25519",
+        data: fromBase64(assertNotEmpty(data.value)),
+      };
+    case "tendermint/PubKeySecp256k1":
+      return {
+        algorithm: "secp256k1",
+        data: fromBase64(assertNotEmpty(data.value)),
+      };
+    default:
+      throw new Error(`unknown pubkey type: ${data.type}`);
   }
-  throw new Error(`unknown pubkey type: ${data.type}`);
 }
 
 // for evidence, block results, etc.
diff --git a/packages/tendermint-rpc/src/tendermint34/adaptors/v0-34/responses.ts b/packages/tendermint-rpc/src/tendermint34/adaptors/v0-34/responses.ts
index 84c2ea33..5386c7e1 100644
--- a/packages/tendermint-rpc/src/tendermint34/adaptors/v0-34/responses.ts
+++ b/packages/tendermint-rpc/src/tendermint34/adaptors/v0-34/responses.ts
@@ -156,14 +156,21 @@ interface RpcPubkey {
 }
 
 function decodePubkey(data: RpcPubkey): ValidatorPubkey {
-  if (data.type === "tendermint/PubKeyEd25519") {
+  switch (data.type) {
     // go-amino special code
-    return {
-      algorithm: "ed25519",
-      data: fromBase64(assertNotEmpty(data.value)),
-    };
+    case "tendermint/PubKeyEd25519":
+      return {
+        algorithm: "ed25519",
+        data: fromBase64(assertNotEmpty(data.value)),
+      };
+    case "tendermint/PubKeySecp256k1":
+      return {
+        algorithm: "secp256k1",
+        data: fromBase64(assertNotEmpty(data.value)),
+      };
+    default:
+      throw new Error(`unknown pubkey type: ${data.type}`);
   }
-  throw new Error(`unknown pubkey type: ${data.type}`);
 }
 
 // for evidence, block results, etc.
diff --git a/packages/tendermint-rpc/src/types.ts b/packages/tendermint-rpc/src/types.ts
index ae0c74b0..faa5dcec 100644
--- a/packages/tendermint-rpc/src/types.ts
+++ b/packages/tendermint-rpc/src/types.ts
@@ -8,11 +8,15 @@ export interface ValidatorEd25519Pubkey {
   readonly data: Uint8Array;
 }
 
+export interface ValidatorSecp256k1Pubkey {
+  readonly algorithm: "secp256k1";
+  readonly data: Uint8Array;
+}
+
 /**
  * Union type for different possible pubkeys.
- * Currently only Ed25519 supported.
  */
-export type ValidatorPubkey = ValidatorEd25519Pubkey;
+export type ValidatorPubkey = ValidatorEd25519Pubkey | ValidatorSecp256k1Pubkey;
 
 export enum BlockIdFlag {
   Unknown = 0,