diff --git a/package.json b/package.json
index 08e99ef..27c5a62 100644
--- a/package.json
+++ b/package.json
@@ -1,6 +1,6 @@
 {
   "name": "@eppo/js-client-sdk",
-  "version": "0.0.5",
+  "version": "0.0.6",
   "description": "Eppo SDK for client-side JavaScript applications",
   "main": "dist/index.js",
   "files": [
diff --git a/src/rule_evaluator.spec.ts b/src/rule_evaluator.spec.ts
index 5618d54..8323553 100644
--- a/src/rule_evaluator.spec.ts
+++ b/src/rule_evaluator.spec.ts
@@ -117,6 +117,33 @@ describe('matchesAnyRule', () => {
     expect(matchesAnyRule({ userId: 'user15' }, [notOneOfRule])).toEqual(true);
   });
 
+  it('does case insensitive matching with oneOf operator', () => {
+    const oneOfRule: Rule = {
+      conditions: [
+        {
+          operator: OperatorType.ONE_OF,
+          value: ['CA', 'US'],
+          attribute: 'country',
+        },
+      ],
+    };
+    expect(matchesAnyRule({ country: 'us' }, [oneOfRule])).toEqual(true);
+    expect(matchesAnyRule({ country: 'cA' }, [oneOfRule])).toEqual(true);
+  });
+
+  it('does case insensitive matching with notOneOf operator', () => {
+    const notOneOf: Rule = {
+      conditions: [
+        {
+          operator: OperatorType.NOT_ONE_OF,
+          value: ['1.0.BB', '1Ab'],
+          attribute: 'deviceType',
+        },
+      ],
+    };
+    expect(matchesAnyRule({ deviceType: '1ab' }, [notOneOf])).toEqual(false);
+  });
+
   it('handles oneOf rule with number', () => {
     const oneOfRule: Rule = {
       conditions: [
diff --git a/src/rule_evaluator.ts b/src/rule_evaluator.ts
index 08bc604..09fb7b5 100644
--- a/src/rule_evaluator.ts
+++ b/src/rule_evaluator.ts
@@ -46,11 +46,15 @@ function evaluateCondition(subjectAttributes: Record<string, any>, condition: Co
 }
 
 function isOneOf(attributeValue: any, conditionValue: string[]) {
-  return conditionValue.includes(attributeValue.toString());
+  return getMatchingStringValues(attributeValue.toString(), conditionValue).length > 0;
 }
 
 function isNotOneOf(attributeValue: any, conditionValue: string[]) {
-  return !conditionValue.includes(attributeValue.toString());
+  return getMatchingStringValues(attributeValue.toString(), conditionValue).length === 0;
+}
+
+function getMatchingStringValues(attributeValue: string, conditionValues: string[]): string[] {
+  return conditionValues.filter((value) => value.toLowerCase() === attributeValue.toLowerCase());
 }
 
 function compareNumber(