diff --git a/specs/validate-helpers-spec.js b/specs/validate-helpers-spec.js
index 5c06953..cb630f1 100644
--- a/specs/validate-helpers-spec.js
+++ b/specs/validate-helpers-spec.js
@@ -328,6 +328,22 @@ describe("validate", function() {
       it("works with empty objects", function() {
         expect(contains({}, "foo")).toBe(false);
       });
+
+      describe("case insensitive", function() {
+        it("returns true if the value is a key in the object", function() {
+          expect(contains({foo: false, bar: "bar"}, "foo", true)).toBe(true);
+          expect(contains({Foo: false, bar: "bar"}, "foo", true)).toBe(true);
+          expect(contains({foo: false, bar: "bar"}, "BaR", true)).toBe(true);
+        });
+        
+        it("returns false if the value is not a key in the object", function() {
+          expect(contains({foo: false, bar: "bar"}, "quux", true)).toBe(false);
+          expect(contains({foo: false, bar: "bar"}, null, true)).toBe(false);
+          expect(contains({foo: false, bar: "bar"}, 1, true)).toBe(false);
+          expect(contains({foo: false, bar: "bar"}, true, true)).toBe(false);
+        });
+      });
+
     });
   });
 
diff --git a/specs/validators/exclusion-spec.js b/specs/validators/exclusion-spec.js
index d31d6f9..eefdf5c 100644
--- a/specs/validators/exclusion-spec.js
+++ b/specs/validators/exclusion-spec.js
@@ -56,6 +56,19 @@ describe("validators.exclusion", function() {
     expect(exclusion("baz", ["foo", "bar"])).not.toBeDefined();
   });
 
+  describe("caseSensitive false", function() {
+    it("finds keys if the within value is an object", function() {
+      expect(exclusion("Foo", {within: {foO: true}, caseSensitive: false })).toBeDefined();
+      expect(exclusion("foo", {within: {foo: true, caseSensitive: false}})).toBeDefined();
+    });
+
+    it("finds options if within value is an array", function() {
+      expect(exclusion("Foo", {within: ["foo", "bar"], caseSensitive: false })).toBeDefined();
+      expect(exclusion("bar", {within: ["foo", "BaR"], caseSensitive: false })).toBeDefined();
+      expect(exclusion("bar", {within: ["foo", "bar"], caseSensitive: false })).toBeDefined();
+    });
+  });
+
   it("supports default options", function() {
     validate.validators.exclusion.options = {
       message: "barfoo",
diff --git a/specs/validators/inclusion-spec.js b/specs/validators/inclusion-spec.js
index 950280d..5a332a7 100644
--- a/specs/validators/inclusion-spec.js
+++ b/specs/validators/inclusion-spec.js
@@ -47,6 +47,21 @@ describe("validators.inclusion", function() {
     expect(inclusion("baz", ["foo", "bar"])).toBeDefined();
   });
 
+  describe("caseSensitive false", function() {
+    it("finds keys if the within value is an object", function() {
+      expect(inclusion("Foo", {within: {foo: true}, caseSensitive: false })).not.toBeDefined();
+      expect(inclusion("foo", {within: {fOO: true}, caseSensitive: false })).not.toBeDefined();
+      expect(inclusion("bar", {within: {fOO: true}, caseSensitive: false })).toBeDefined();
+    });
+  
+    it("finds options if the within value is an array", function() {
+      expect(inclusion("Foo", {within: ["foo", "bar"], caseSensitive: false })).not.toBeDefined();
+      expect(inclusion("bar", {within: ["foo", "BaR"], caseSensitive: false })).not.toBeDefined();
+      expect(inclusion("bar", {within: ["foo", "bar"], caseSensitive: false })).not.toBeDefined();
+      expect(inclusion("baz", {within: ["foo", "bar"], caseSensitive: false })).toBeDefined();
+    });
+  });
+
   it("supports default options", function() {
     validate.validators.inclusion.options = {
       message: "barfoo",
diff --git a/validate.js b/validate.js
index adf023b..0c87688 100644
--- a/validate.js
+++ b/validate.js
@@ -430,14 +430,31 @@
       return v.isObject(value) && !v.isArray(value) && !v.isFunction(value);
     },
 
-    contains: function(obj, value) {
+    contains: function(obj, value, caseInsensitive) {
+      var caseSensitive = !caseInsensitive;
+      var toLowerCase = function (k) {
+        return k && k.toLowerCase ? k.toLowerCase() : k;
+      };
+ 
       if (!v.isDefined(obj)) {
         return false;
       }
       if (v.isArray(obj)) {
-        return obj.indexOf(value) !== -1;
+        if (caseSensitive) {
+          return obj.indexOf(value) !== -1;
+        }
+        return obj.map(toLowerCase).indexOf(toLowerCase(value)) !== -1;
       }
-      return value in obj;
+      
+      var valueIsInObj = value in obj;
+      
+      if (caseSensitive || valueIsInObj) {
+        return valueIsInObj;
+      }
+
+      return Object.keys(obj)
+        .map(toLowerCase)
+        .indexOf(toLowerCase(value)) !== -1;
     },
 
     unique: function(array) {
@@ -1021,7 +1038,8 @@
         options = {within: options};
       }
       options = v.extend({}, this.options, options);
-      if (v.contains(options.within, value)) {
+      var caseInsensitive = options.caseSensitive === false;
+      if (v.contains(options.within, value, caseInsensitive)) {
         return;
       }
       var message = options.message ||
@@ -1038,7 +1056,8 @@
         options = {within: options};
       }
       options = v.extend({}, this.options, options);
-      if (!v.contains(options.within, value)) {
+      var caseInsensitive = options.caseSensitive === false;
+      if (!v.contains(options.within, value, caseInsensitive)) {
         return;
       }
       var message = options.message || this.message || "^%{value} is restricted";