diff --git a/CHANGELOG.md b/CHANGELOG.md
index d83dce78..8fa3d3d1 100644
--- a/CHANGELOG.md
+++ b/CHANGELOG.md
@@ -6,6 +6,10 @@ and this project adheres to
 
 ## [Unreleased]
 
+### Added
+
+- @cosmjs/encoding: Create `normalizeBech32`.
+
 ## [0.28.1] - 2022-03-30
 
 ### Added
diff --git a/packages/encoding/src/bech32.spec.ts b/packages/encoding/src/bech32.spec.ts
index 39194cfd..1806ddc4 100644
--- a/packages/encoding/src/bech32.spec.ts
+++ b/packages/encoding/src/bech32.spec.ts
@@ -1,12 +1,12 @@
-import { fromBech32, toBech32 } from "./bech32";
+import { fromBech32, normalizeBech32, toBech32 } from "./bech32";
 import { fromHex } from "./hex";
 
-describe("Bech32", () => {
+describe("bech32", () => {
   // test data generate using https://github.com/nym-zone/bech32
   // bech32 -e -h eth 9d4e856e572e442f0a4b2763e72d08a0e99d8ded
   const ethAddressRaw = fromHex("9d4e856e572e442f0a4b2763e72d08a0e99d8ded");
 
-  describe("encode", () => {
+  describe("toBech32", () => {
     it("works", () => {
       expect(toBech32("eth", ethAddressRaw)).toEqual("eth1n48g2mjh9ezz7zjtya37wtgg5r5emr0drkwlgw");
     });
@@ -44,7 +44,7 @@ describe("Bech32", () => {
     });
   });
 
-  describe("decode", () => {
+  describe("fromBech32", () => {
     it("works", () => {
       expect(fromBech32("eth1n48g2mjh9ezz7zjtya37wtgg5r5emr0drkwlgw")).toEqual({
         prefix: "eth",
@@ -52,6 +52,15 @@ describe("Bech32", () => {
       });
     });
 
+    it("works for upper case address", () => {
+      // "For presentation, lowercase is usually preferable, but inside QR codes uppercase SHOULD be used, as those permit the use of alphanumeric mode, which is 45% more compact than the normal byte mode."
+      // https://github.com/bitcoin/bips/blob/master/bip-0173.mediawiki
+      expect(fromBech32("ETH1N48G2MJH9EZZ7ZJTYA37WTGG5R5EMR0DRKWLGW")).toEqual({
+        prefix: "eth",
+        data: ethAddressRaw,
+      });
+    });
+
     it("works for addresses which exceed the specification limit of 90 characters", () => {
       // Example from https://github.com/cosmos/cosmos-sdk/pull/6237#issuecomment-658116534
       expect(() =>
@@ -70,5 +79,34 @@ describe("Bech32", () => {
         ),
       ).toThrowError(/exceeds length limit/i);
     });
+
+    it("throws for mixed case addresses", () => {
+      // "Decoders MUST NOT accept strings where some characters are uppercase and some are lowercase (such strings are referred to as mixed case strings)."
+      // https://github.com/bitcoin/bips/blob/master/bip-0173.mediawiki
+      expect(() => fromBech32("Eth1n48g2mjh9ezz7zjtya37wtgg5r5emr0drkwlgw")).toThrowError(/Mixed-case/i);
+      expect(() => fromBech32("eTh1n48g2mjh9ezz7zjtya37wtgg5r5emr0drkwlgw")).toThrowError(/Mixed-case/i);
+      expect(() => fromBech32("ETH1n48g2mjh9ezz7zjtya37wtgg5r5emr0drkwlgw")).toThrowError(/Mixed-case/i);
+      expect(() => fromBech32("eth1n48g2mjh9Ezz7zjtya37wtgg5r5emr0drkwlgw")).toThrowError(/Mixed-case/i);
+    });
+  });
+
+  describe("normalizeBech32", () => {
+    it("works", () => {
+      expect(normalizeBech32("eth1n48g2mjh9ezz7zjtya37wtgg5r5emr0drkwlgw")).toEqual(
+        "eth1n48g2mjh9ezz7zjtya37wtgg5r5emr0drkwlgw",
+      );
+      expect(normalizeBech32("ETH1N48G2MJH9EZZ7ZJTYA37WTGG5R5EMR0DRKWLGW")).toEqual(
+        "eth1n48g2mjh9ezz7zjtya37wtgg5r5emr0drkwlgw",
+      );
+    });
+
+    it("throws for mixed case addresses", () => {
+      // "Decoders MUST NOT accept strings where some characters are uppercase and some are lowercase (such strings are referred to as mixed case strings)."
+      // https://github.com/bitcoin/bips/blob/master/bip-0173.mediawiki
+      expect(() => normalizeBech32("Eth1n48g2mjh9ezz7zjtya37wtgg5r5emr0drkwlgw")).toThrowError(/Mixed-case/i);
+      expect(() => normalizeBech32("eTh1n48g2mjh9ezz7zjtya37wtgg5r5emr0drkwlgw")).toThrowError(/Mixed-case/i);
+      expect(() => normalizeBech32("ETH1n48g2mjh9ezz7zjtya37wtgg5r5emr0drkwlgw")).toThrowError(/Mixed-case/i);
+      expect(() => normalizeBech32("eth1n48g2mjh9Ezz7zjtya37wtgg5r5emr0drkwlgw")).toThrowError(/Mixed-case/i);
+    });
   });
 });
diff --git a/packages/encoding/src/bech32.ts b/packages/encoding/src/bech32.ts
index 38d4803e..d333611a 100644
--- a/packages/encoding/src/bech32.ts
+++ b/packages/encoding/src/bech32.ts
@@ -16,6 +16,17 @@ export function fromBech32(
   };
 }
 
+/**
+ * Takes a bech32 address and returns a normalized (i.e. lower case) representation of it.
+ *
+ * The input is validated along the way, which makes this significantly safer than
+ * using `address.toLowerCase()`.
+ */
+export function normalizeBech32(address: string): string {
+  const { prefix, data } = fromBech32(address);
+  return toBech32(prefix, data);
+}
+
 /**
  * @deprecated This class is deprecated and will be removed soon. Please use fromBech32() and toBech32() instead. For more details please refer to https://github.com/cosmos/cosmjs/issues/1053.
  */