diff --git a/scripts/genesis/Denylist.ts b/scripts/genesis/Denylist.ts
index 05e034c1..95b7ec2b 100644
--- a/scripts/genesis/Denylist.ts
+++ b/scripts/genesis/Denylist.ts
@@ -15,6 +15,7 @@
 // limitations under the License.
 
 import { z } from 'zod'
+import { zeroAddress } from 'viem'
 import {
   addressToBytes32,
   buildImplContractAlloc,
@@ -61,6 +62,37 @@ export const schemaDenylist = z
       { key: 'owner', value: data.owner },
       ...(data.denylisters ?? []).map((d, i) => ({ key: `denylisters[${i}]`, value: d })),
     ])
+
+    if (data.owner.toLowerCase() === zeroAddress.toLowerCase()) {
+      ctx.addIssue({
+        code: z.ZodIssueCode.custom,
+        path: ['owner'],
+        message: 'Owner cannot be the zero address',
+      })
+    }
+
+    const denylisterSet = new Set<string>()
+    for (let i = 0; i < (data.denylisters ?? []).length; i++) {
+      const denylister = data.denylisters![i]
+      const normalized = denylister.toLowerCase()
+
+      if (normalized === zeroAddress.toLowerCase()) {
+        ctx.addIssue({
+          code: z.ZodIssueCode.custom,
+          path: ['denylisters', i],
+          message: `Denylister ${denylister} cannot be the zero address`,
+        })
+      }
+
+      if (denylisterSet.has(normalized)) {
+        ctx.addIssue({
+          code: z.ZodIssueCode.custom,
+          path: ['denylisters', i],
+          message: `Denylister ${denylister} must be unique`,
+        })
+      }
+      denylisterSet.add(normalized)
+    }
   })
 
 export type DenylistConfig = z.infer<typeof schemaDenylist>
diff --git a/tests/unit/denylist-genesis.test.ts b/tests/unit/denylist-genesis.test.ts
new file mode 100644
index 00000000..abdaab26
--- /dev/null
+++ b/tests/unit/denylist-genesis.test.ts
@@ -0,0 +1,122 @@
+// Copyright 2026 Circle Internet Group, Inc. All rights reserved.
+//
+// SPDX-License-Identifier: Apache-2.0
+//
+// Licensed under the Apache License, Version 2.0 (the "License");
+// you may not use this file except in compliance with the License.
+// You may obtain a copy of the License at
+//
+//      http://www.apache.org/licenses/LICENSE-2.0
+//
+// Unless required by applicable law or agreed to in writing, software
+// distributed under the License is distributed on an "AS IS" BASIS,
+// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+// See the License for the specific language governing permissions and
+// limitations under the License.
+
+import { expect } from 'chai'
+import { zeroAddress } from 'viem'
+import { schemaDenylist } from '../../scripts/genesis/Denylist'
+
+const proxyAdmin = '0x1111111111111111111111111111111111111111'
+const owner = '0x2222222222222222222222222222222222222222'
+const denylisterA = '0x3333333333333333333333333333333333333333'
+const denylisterB = '0x4444444444444444444444444444444444444444'
+
+const baseConfig = {
+  proxy: {
+    admin: proxyAdmin,
+  },
+  owner,
+  denylisters: [denylisterA, denylisterB],
+}
+
+describe('Denylist genesis schema', () => {
+  it('accepts a valid config with denylisters', () => {
+    expect(() => schemaDenylist.parse(baseConfig)).to.not.throw()
+  })
+
+  it('accepts a valid config with omitted denylisters', () => {
+    const { denylisters: _, ...configWithoutDenylisters } = baseConfig
+    expect(() => schemaDenylist.parse(configWithoutDenylisters)).to.not.throw()
+  })
+
+  it('accepts a valid config with empty denylisters array', () => {
+    expect(() => schemaDenylist.parse({ ...baseConfig, denylisters: [] })).to.not.throw()
+  })
+
+  it('rejects zero address as owner', () => {
+    const result = schemaDenylist.safeParse({
+      ...baseConfig,
+      owner: zeroAddress,
+    })
+
+    expect(result.success).to.be.false
+    if (!result.success) {
+      expect(result.error.issues.some((issue) => issue.message.includes('Owner cannot be the zero address'))).to.be.true
+    }
+  })
+
+  it('rejects zero address in denylisters', () => {
+    const result = schemaDenylist.safeParse({
+      ...baseConfig,
+      denylisters: [denylisterA, zeroAddress],
+    })
+
+    expect(result.success).to.be.false
+    if (!result.success) {
+      expect(result.error.issues.some((issue) => issue.message.includes('cannot be the zero address'))).to.be.true
+    }
+  })
+
+  it('rejects duplicate denylisters', () => {
+    const result = schemaDenylist.safeParse({
+      ...baseConfig,
+      denylisters: [denylisterA, denylisterB, denylisterA],
+    })
+
+    expect(result.success).to.be.false
+    if (!result.success) {
+      expect(result.error.issues.some((issue) => issue.message.includes('must be unique'))).to.be.true
+    }
+  })
+
+  it('rejects duplicate denylisters with mixed casing', () => {
+    const denylisterAUpper = `0x${denylisterA.slice(2).toUpperCase()}` as const
+    const result = schemaDenylist.safeParse({
+      ...baseConfig,
+      denylisters: [denylisterA, denylisterAUpper],
+    })
+
+    expect(result.success).to.be.false
+    if (!result.success) {
+      expect(result.error.issues.some((issue) => issue.message.includes('must be unique'))).to.be.true
+    }
+  })
+
+  it('rejects when owner is the same as proxy admin', () => {
+    const result = schemaDenylist.safeParse({
+      ...baseConfig,
+      owner: proxyAdmin,
+    })
+
+    expect(result.success).to.be.false
+    if (!result.success) {
+      expect(result.error.issues.some((issue) => issue.message.includes('cannot be the same as the proxy admin'))).to.be
+        .true
+    }
+  })
+
+  it('rejects when a denylister is the same as proxy admin', () => {
+    const result = schemaDenylist.safeParse({
+      ...baseConfig,
+      denylisters: [denylisterA, proxyAdmin],
+    })
+
+    expect(result.success).to.be.false
+    if (!result.success) {
+      expect(result.error.issues.some((issue) => issue.message.includes('cannot be the same as the proxy admin'))).to.be
+        .true
+    }
+  })
+})