diff --git a/lib/jasmine-core/jasmine-html.js b/lib/jasmine-core/jasmine-html.js
index 454061b2..f6125b1a 100644
--- a/lib/jasmine-core/jasmine-html.js
+++ b/lib/jasmine-core/jasmine-html.js
@@ -903,7 +903,7 @@ jasmineRequire.htmlReporterUtils = function(j$) {
     const el = document.createElement(type);
     let children;
 
-    if (j$.private.isArray(childrenArrayOrVarArgs)) {
+    if (Array.isArray(childrenArrayOrVarArgs)) {
       children = childrenArrayOrVarArgs;
     } else {
       children = [];
diff --git a/lib/jasmine-core/jasmine.js b/lib/jasmine-core/jasmine.js
index 63b9ee84..08d7c19f 100644
--- a/lib/jasmine-core/jasmine.js
+++ b/lib/jasmine-core/jasmine.js
@@ -275,10 +275,6 @@ getJasmineRequireObj().base = function(j$, jasmineGlobal) {
     }
   });
 
-  j$.private.isArray = function(value) {
-    return j$.private.isA('Array', value);
-  };
-
   j$.private.isObject = function(value) {
     return (
       value !== undefined && value !== null && j$.private.isA('Object', value)
@@ -2332,7 +2328,7 @@ getJasmineRequireObj().ArrayContaining = function(j$) {
   }
 
   ArrayContaining.prototype.asymmetricMatch = function(other, matchersUtil) {
-    if (!j$.private.isArray(this.sample)) {
+    if (!Array.isArray(this.sample)) {
       throw new Error(
         'You must provide an array to arrayContaining, not ' +
           j$.private.basicPrettyPrinter(this.sample) +
@@ -2343,7 +2339,7 @@ getJasmineRequireObj().ArrayContaining = function(j$) {
     // If the actual parameter is not an array, we can fail immediately, since it couldn't
     // possibly be an "array containing" anything. However, we also want an empty sample
     // array to match anything, so we need to double-check we aren't in that case
-    if (!j$.private.isArray(other) && this.sample.length > 0) {
+    if (!Array.isArray(other) && this.sample.length > 0) {
       return false;
     }
 
@@ -2374,7 +2370,7 @@ getJasmineRequireObj().ArrayWithExactContents = function(j$) {
     other,
     matchersUtil
   ) {
-    if (!j$.private.isArray(this.sample)) {
+    if (!Array.isArray(this.sample)) {
       throw new Error(
         'You must provide an array to arrayWithExactContents, not ' +
           j$.private.basicPrettyPrinter(this.sample) +
@@ -2410,7 +2406,7 @@ getJasmineRequireObj().Empty = function(j$) {
   Empty.prototype.asymmetricMatch = function(other) {
     if (
       j$.private.isString(other) ||
-      j$.private.isArray(other) ||
+      Array.isArray(other) ||
       j$.private.isTypedArray(other)
     ) {
       return other.length === 0;
@@ -2525,7 +2521,7 @@ getJasmineRequireObj().NotEmpty = function(j$) {
   NotEmpty.prototype.asymmetricMatch = function(other) {
     if (
       j$.private.isString(other) ||
-      j$.private.isArray(other) ||
+      Array.isArray(other) ||
       j$.private.isTypedArray(other)
     ) {
       return other.length !== 0;
@@ -8263,7 +8259,7 @@ getJasmineRequireObj().makePrettyPrinter = function(j$) {
         } else if (
           value.toString &&
           typeof value === 'object' &&
-          !j$.private.isArray(value) &&
+          !Array.isArray(value) &&
           hasCustomToString(value)
         ) {
           try {
@@ -8275,15 +8271,12 @@ getJasmineRequireObj().makePrettyPrinter = function(j$) {
         } else if (this.seen.includes(value)) {
           this.emitScalar(
             '<circular reference: ' +
-              (j$.private.isArray(value) ? 'Array' : 'Object') +
+              (Array.isArray(value) ? 'Array' : 'Object') +
               '>'
           );
-        } else if (
-          j$.private.isArray(value) ||
-          j$.private.isA('Object', value)
-        ) {
+        } else if (Array.isArray(value) || j$.private.isA('Object', value)) {
           this.seen.push(value);
-          if (j$.private.isArray(value)) {
+          if (Array.isArray(value)) {
             this.emitArray(value);
           } else {
             this.emitObject(value);
@@ -8306,10 +8299,7 @@ getJasmineRequireObj().makePrettyPrinter = function(j$) {
     }
 
     iterateObject(obj, fn) {
-      const objKeys = j$.private.MatchersUtil.keys(
-        obj,
-        j$.private.isArray(obj)
-      );
+      const objKeys = j$.private.MatchersUtil.keys(obj, Array.isArray(obj));
       const length = Math.min(objKeys.length, j$.MAX_PRETTY_PRINT_ARRAY_LENGTH);
 
       for (let i = 0; i < length; i++) {
@@ -10237,7 +10227,7 @@ getJasmineRequireObj().SpyFactory = function(j$) {
 
     this.createSpyObj = function(baseName, methodNames, propertyNames) {
       const baseNameIsCollection =
-        j$.private.isObject(baseName) || j$.private.isArray(baseName);
+        j$.private.isObject(baseName) || Array.isArray(baseName);
 
       if (baseNameIsCollection) {
         propertyNames = methodNames;
@@ -10283,7 +10273,7 @@ getJasmineRequireObj().SpyFactory = function(j$) {
 
   function normalizeKeyValues(object) {
     const result = [];
-    if (j$.private.isArray(object)) {
+    if (Array.isArray(object)) {
       for (let i = 0; i < object.length; i++) {
         result.push([object[i]]);
       }
diff --git a/spec/core/RunnerSpec.js b/spec/core/RunnerSpec.js
index 84667e53..2b2bcfe2 100644
--- a/spec/core/RunnerSpec.js
+++ b/spec/core/RunnerSpec.js
@@ -87,7 +87,7 @@ describe('Runner', function() {
     function arrayNotContaining(item) {
       return {
         asymmetricMatch(other, matchersUtil) {
-          if (!jasmine.private.isArray(other)) {
+          if (!Array.isArray(other)) {
             return false;
           }
 
diff --git a/spec/core/UtilSpec.js b/spec/core/UtilSpec.js
index 6a0abc0a..0ab7d919 100644
--- a/spec/core/UtilSpec.js
+++ b/spec/core/UtilSpec.js
@@ -1,20 +1,4 @@
 describe('util', function() {
-  describe('isArray', function() {
-    it('should return true if the argument is an array', function() {
-      expect(privateUnderTest.isArray([])).toBe(true);
-      expect(privateUnderTest.isArray(['a'])).toBe(true);
-    });
-
-    it('should return false if the argument is not an array', function() {
-      expect(privateUnderTest.isArray(undefined)).toBe(false);
-      expect(privateUnderTest.isArray({})).toBe(false);
-      expect(privateUnderTest.isArray(function() {})).toBe(false);
-      expect(privateUnderTest.isArray('foo')).toBe(false);
-      expect(privateUnderTest.isArray(5)).toBe(false);
-      expect(privateUnderTest.isArray(null)).toBe(false);
-    });
-  });
-
   describe('isObject', function() {
     it('should return true if the argument is an object', function() {
       expect(privateUnderTest.isObject({})).toBe(true);
diff --git a/src/core/PrettyPrinter.js b/src/core/PrettyPrinter.js
index 8c358680..9e506bce 100644
--- a/src/core/PrettyPrinter.js
+++ b/src/core/PrettyPrinter.js
@@ -59,7 +59,7 @@ getJasmineRequireObj().makePrettyPrinter = function(j$) {
         } else if (
           value.toString &&
           typeof value === 'object' &&
-          !j$.private.isArray(value) &&
+          !Array.isArray(value) &&
           hasCustomToString(value)
         ) {
           try {
@@ -71,15 +71,12 @@ getJasmineRequireObj().makePrettyPrinter = function(j$) {
         } else if (this.seen.includes(value)) {
           this.emitScalar(
             '<circular reference: ' +
-              (j$.private.isArray(value) ? 'Array' : 'Object') +
+              (Array.isArray(value) ? 'Array' : 'Object') +
               '>'
           );
-        } else if (
-          j$.private.isArray(value) ||
-          j$.private.isA('Object', value)
-        ) {
+        } else if (Array.isArray(value) || j$.private.isA('Object', value)) {
           this.seen.push(value);
-          if (j$.private.isArray(value)) {
+          if (Array.isArray(value)) {
             this.emitArray(value);
           } else {
             this.emitObject(value);
@@ -102,10 +99,7 @@ getJasmineRequireObj().makePrettyPrinter = function(j$) {
     }
 
     iterateObject(obj, fn) {
-      const objKeys = j$.private.MatchersUtil.keys(
-        obj,
-        j$.private.isArray(obj)
-      );
+      const objKeys = j$.private.MatchersUtil.keys(obj, Array.isArray(obj));
       const length = Math.min(objKeys.length, j$.MAX_PRETTY_PRINT_ARRAY_LENGTH);
 
       for (let i = 0; i < length; i++) {
diff --git a/src/core/SpyFactory.js b/src/core/SpyFactory.js
index 26a768be..dfb669d9 100644
--- a/src/core/SpyFactory.js
+++ b/src/core/SpyFactory.js
@@ -21,7 +21,7 @@ getJasmineRequireObj().SpyFactory = function(j$) {
 
     this.createSpyObj = function(baseName, methodNames, propertyNames) {
       const baseNameIsCollection =
-        j$.private.isObject(baseName) || j$.private.isArray(baseName);
+        j$.private.isObject(baseName) || Array.isArray(baseName);
 
       if (baseNameIsCollection) {
         propertyNames = methodNames;
@@ -67,7 +67,7 @@ getJasmineRequireObj().SpyFactory = function(j$) {
 
   function normalizeKeyValues(object) {
     const result = [];
-    if (j$.private.isArray(object)) {
+    if (Array.isArray(object)) {
       for (let i = 0; i < object.length; i++) {
         result.push([object[i]]);
       }
diff --git a/src/core/asymmetric_equality/ArrayContaining.js b/src/core/asymmetric_equality/ArrayContaining.js
index 7560df19..e2408e19 100644
--- a/src/core/asymmetric_equality/ArrayContaining.js
+++ b/src/core/asymmetric_equality/ArrayContaining.js
@@ -6,7 +6,7 @@ getJasmineRequireObj().ArrayContaining = function(j$) {
   }
 
   ArrayContaining.prototype.asymmetricMatch = function(other, matchersUtil) {
-    if (!j$.private.isArray(this.sample)) {
+    if (!Array.isArray(this.sample)) {
       throw new Error(
         'You must provide an array to arrayContaining, not ' +
           j$.private.basicPrettyPrinter(this.sample) +
@@ -17,7 +17,7 @@ getJasmineRequireObj().ArrayContaining = function(j$) {
     // If the actual parameter is not an array, we can fail immediately, since it couldn't
     // possibly be an "array containing" anything. However, we also want an empty sample
     // array to match anything, so we need to double-check we aren't in that case
-    if (!j$.private.isArray(other) && this.sample.length > 0) {
+    if (!Array.isArray(other) && this.sample.length > 0) {
       return false;
     }
 
diff --git a/src/core/asymmetric_equality/ArrayWithExactContents.js b/src/core/asymmetric_equality/ArrayWithExactContents.js
index 2d5f5172..104049b2 100644
--- a/src/core/asymmetric_equality/ArrayWithExactContents.js
+++ b/src/core/asymmetric_equality/ArrayWithExactContents.js
@@ -9,7 +9,7 @@ getJasmineRequireObj().ArrayWithExactContents = function(j$) {
     other,
     matchersUtil
   ) {
-    if (!j$.private.isArray(this.sample)) {
+    if (!Array.isArray(this.sample)) {
       throw new Error(
         'You must provide an array to arrayWithExactContents, not ' +
           j$.private.basicPrettyPrinter(this.sample) +
diff --git a/src/core/asymmetric_equality/Empty.js b/src/core/asymmetric_equality/Empty.js
index 097238ad..7cab0544 100644
--- a/src/core/asymmetric_equality/Empty.js
+++ b/src/core/asymmetric_equality/Empty.js
@@ -6,7 +6,7 @@ getJasmineRequireObj().Empty = function(j$) {
   Empty.prototype.asymmetricMatch = function(other) {
     if (
       j$.private.isString(other) ||
-      j$.private.isArray(other) ||
+      Array.isArray(other) ||
       j$.private.isTypedArray(other)
     ) {
       return other.length === 0;
diff --git a/src/core/asymmetric_equality/NotEmpty.js b/src/core/asymmetric_equality/NotEmpty.js
index 088a053f..b4c8660b 100644
--- a/src/core/asymmetric_equality/NotEmpty.js
+++ b/src/core/asymmetric_equality/NotEmpty.js
@@ -6,7 +6,7 @@ getJasmineRequireObj().NotEmpty = function(j$) {
   NotEmpty.prototype.asymmetricMatch = function(other) {
     if (
       j$.private.isString(other) ||
-      j$.private.isArray(other) ||
+      Array.isArray(other) ||
       j$.private.isTypedArray(other)
     ) {
       return other.length !== 0;
diff --git a/src/core/base.js b/src/core/base.js
index 2680987a..95d5bdef 100644
--- a/src/core/base.js
+++ b/src/core/base.js
@@ -77,10 +77,6 @@ getJasmineRequireObj().base = function(j$, jasmineGlobal) {
     }
   });
 
-  j$.private.isArray = function(value) {
-    return j$.private.isA('Array', value);
-  };
-
   j$.private.isObject = function(value) {
     return (
       value !== undefined && value !== null && j$.private.isA('Object', value)
diff --git a/src/html/htmlReporterUtils.js b/src/html/htmlReporterUtils.js
index a371413b..6a4e407d 100644
--- a/src/html/htmlReporterUtils.js
+++ b/src/html/htmlReporterUtils.js
@@ -5,7 +5,7 @@ jasmineRequire.htmlReporterUtils = function(j$) {
     const el = document.createElement(type);
     let children;
 
-    if (j$.private.isArray(childrenArrayOrVarArgs)) {
+    if (Array.isArray(childrenArrayOrVarArgs)) {
       children = childrenArrayOrVarArgs;
     } else {
       children = [];