diff --git a/x-pack/legacy/plugins/spaces/server/lib/space_schema.test.ts b/x-pack/legacy/plugins/spaces/server/lib/space_schema.test.ts
index 6ca37affb84871..719f9a0908a76f 100644
--- a/x-pack/legacy/plugins/spaces/server/lib/space_schema.test.ts
+++ b/x-pack/legacy/plugins/spaces/server/lib/space_schema.test.ts
@@ -62,3 +62,77 @@ describe('#id', () => {
     }
   );
 });
+
+describe('#color', () => {
+  test('is optional', () => {
+    const result = spaceSchema.validate({
+      ...defaultProperties,
+      color: undefined,
+    });
+    expect(result.error).toBeNull();
+  });
+
+  test(`doesn't allow an empty string`, () => {
+    const result = spaceSchema.validate({
+      ...defaultProperties,
+      color: '',
+    });
+    expect(result.error).toMatchInlineSnapshot(
+      `[ValidationError: child "color" fails because ["color" is not allowed to be empty]]`
+    );
+  });
+
+  test(`allows lower case hex color code`, () => {
+    const result = spaceSchema.validate({
+      ...defaultProperties,
+      color: '#aabbcc',
+    });
+    expect(result.error).toBeNull();
+  });
+
+  test(`allows upper case hex color code`, () => {
+    const result = spaceSchema.validate({
+      ...defaultProperties,
+      color: '#AABBCC',
+    });
+    expect(result.error).toBeNull();
+  });
+
+  test(`allows numeric hex color code`, () => {
+    const result = spaceSchema.validate({
+      ...defaultProperties,
+      color: '#123456',
+    });
+    expect(result.error).toBeNull();
+  });
+
+  test(`must start with a hash`, () => {
+    const result = spaceSchema.validate({
+      ...defaultProperties,
+      color: '123456',
+    });
+    expect(result.error).toMatchInlineSnapshot(
+      `[ValidationError: child "color" fails because ["color" with value "123456" fails to match the 6 digit hex color, starting with a # pattern]]`
+    );
+  });
+
+  test(`cannot exceed 6 digits following the hash`, () => {
+    const result = spaceSchema.validate({
+      ...defaultProperties,
+      color: '1234567',
+    });
+    expect(result.error).toMatchInlineSnapshot(
+      `[ValidationError: child "color" fails because ["color" with value "1234567" fails to match the 6 digit hex color, starting with a # pattern]]`
+    );
+  });
+
+  test(`cannot be fewer than 6 digits following the hash`, () => {
+    const result = spaceSchema.validate({
+      ...defaultProperties,
+      color: '12345',
+    });
+    expect(result.error).toMatchInlineSnapshot(
+      `[ValidationError: child "color" fails because ["color" with value "12345" fails to match the 6 digit hex color, starting with a # pattern]]`
+    );
+  });
+});
diff --git a/x-pack/legacy/plugins/spaces/server/lib/space_schema.ts b/x-pack/legacy/plugins/spaces/server/lib/space_schema.ts
index c2dcd3b2b9ac06..824c5f27d5fdab 100644
--- a/x-pack/legacy/plugins/spaces/server/lib/space_schema.ts
+++ b/x-pack/legacy/plugins/spaces/server/lib/space_schema.ts
@@ -12,7 +12,7 @@ export const spaceSchema = Joi.object({
   name: Joi.string().required(),
   description: Joi.string().allow(''),
   initials: Joi.string().max(MAX_SPACE_INITIALS),
-  color: Joi.string().regex(/^#[a-z0-9]{6}$/, `6 digit hex color, starting with a #`),
+  color: Joi.string().regex(/^#[a-zA-Z0-9]{6}$/, `6 digit hex color, starting with a #`),
   disabledFeatures: Joi.array()
     .items(Joi.string())
     .default([]),
diff --git a/x-pack/test/api_integration/apis/spaces/index.ts b/x-pack/test/api_integration/apis/spaces/index.ts
new file mode 100644
index 00000000000000..8b1f492696fb23
--- /dev/null
+++ b/x-pack/test/api_integration/apis/spaces/index.ts
@@ -0,0 +1,15 @@
+/*
+ * Copyright Elasticsearch B.V. and/or licensed to Elasticsearch B.V. under one
+ * or more contributor license agreements. Licensed under the Elastic License;
+ * you may not use this file except in compliance with the Elastic License.
+ */
+import { KibanaFunctionalTestDefaultProviders } from '../../../types/providers';
+
+// eslint-disable-next-line import/no-default-export
+export default function({ loadTestFile }: KibanaFunctionalTestDefaultProviders) {
+  describe('spaces', function() {
+    this.tags('ciGroup6');
+
+    loadTestFile(require.resolve('./space_attributes'));
+  });
+}
diff --git a/x-pack/test/api_integration/apis/spaces/space_attributes.ts b/x-pack/test/api_integration/apis/spaces/space_attributes.ts
new file mode 100644
index 00000000000000..112310214dbb6a
--- /dev/null
+++ b/x-pack/test/api_integration/apis/spaces/space_attributes.ts
@@ -0,0 +1,32 @@
+/*
+ * Copyright Elasticsearch B.V. and/or licensed to Elasticsearch B.V. under one
+ * or more contributor license agreements. Licensed under the Elastic License;
+ * you may not use this file except in compliance with the Elastic License.
+ */
+
+import { KibanaFunctionalTestDefaultProviders } from '../../../types/providers';
+
+// eslint-disable-next-line import/no-default-export
+export default function({ getService }: KibanaFunctionalTestDefaultProviders) {
+  const supertest = getService('supertest');
+
+  describe('space attributes', () => {
+    it('should allow a space to be created with a mixed-case hex color code', async () => {
+      await supertest
+        .post('/api/spaces/space')
+        .set('kbn-xsrf', 'xxx')
+        .send({
+          id: 'api-test-space',
+          name: 'api test space',
+          disabledFeatures: [],
+          color: '#aaBB78',
+        })
+        .expect(200, {
+          id: 'api-test-space',
+          name: 'api test space',
+          disabledFeatures: [],
+          color: '#aaBB78',
+        });
+    });
+  });
+}