diff --git a/lib/__tests__/test.js b/lib/__tests__/test.js
index a2a3e3c..13479df 100644
--- a/lib/__tests__/test.js
+++ b/lib/__tests__/test.js
@@ -11,14 +11,7 @@ test(`Should throw an error if config has error`, () => {
 		order: 'Justice Rains From Above',
 	};
 
-	const pluginRun = postcss([plugin(opts)])
-		.process('', { from: undefined })
-		.then(() => {
-			expect('Plugin should throw an error').toBeFalst();
-		})
-		.catch((err) => {
-			throw err;
-		});
-
-	expect(pluginRun).rejects.toBeTruthy();
+	return expect(postcss([plugin(opts)]).process('', { from: undefined })).rejects.toThrow(
+		'postcss-sorting: order: Should be an array'
+	);
 });
diff --git a/lib/properties-order/__tests__/fixtures/properties-alphabetical-case-insensitive.css b/lib/properties-order/__tests__/fixtures/properties-alphabetical-case-insensitive.css
new file mode 100644
index 0000000..185c451
--- /dev/null
+++ b/lib/properties-order/__tests__/fixtures/properties-alphabetical-case-insensitive.css
@@ -0,0 +1,6 @@
+a {
+	Border: red;
+	align-content: center;
+	font-family: sans-serif;
+	Display: block;
+}
diff --git a/lib/properties-order/__tests__/fixtures/properties-alphabetical-case-insensitive.expected.css b/lib/properties-order/__tests__/fixtures/properties-alphabetical-case-insensitive.expected.css
new file mode 100644
index 0000000..47d722a
--- /dev/null
+++ b/lib/properties-order/__tests__/fixtures/properties-alphabetical-case-insensitive.expected.css
@@ -0,0 +1,6 @@
+a {
+	align-content: center;
+	Border: red;
+	Display: block;
+	font-family: sans-serif;
+}
diff --git a/lib/properties-order/__tests__/fixtures/properties-have-same-name-4.css b/lib/properties-order/__tests__/fixtures/properties-have-same-name-4.css
new file mode 100644
index 0000000..02ab582
--- /dev/null
+++ b/lib/properties-order/__tests__/fixtures/properties-have-same-name-4.css
@@ -0,0 +1,11 @@
+div {
+	position: fixed;
+	top: 0;
+	Top: 0;
+}
+
+div {
+	position: fixed;
+	Top: 0;
+	top: 0;
+}
diff --git a/lib/properties-order/__tests__/fixtures/properties-have-same-name-4.expected.css b/lib/properties-order/__tests__/fixtures/properties-have-same-name-4.expected.css
new file mode 100644
index 0000000..02ab582
--- /dev/null
+++ b/lib/properties-order/__tests__/fixtures/properties-have-same-name-4.expected.css
@@ -0,0 +1,11 @@
+div {
+	position: fixed;
+	top: 0;
+	Top: 0;
+}
+
+div {
+	position: fixed;
+	Top: 0;
+	top: 0;
+}
diff --git a/lib/properties-order/__tests__/fixtures/properties-have-same-name-5.css b/lib/properties-order/__tests__/fixtures/properties-have-same-name-5.css
new file mode 100644
index 0000000..ee7d0e9
--- /dev/null
+++ b/lib/properties-order/__tests__/fixtures/properties-have-same-name-5.css
@@ -0,0 +1,9 @@
+.header {
+	Padding-bottom: 20px;
+	Justify-content: space-between;
+	display: -webkit-box;
+	Display: -ms-flexbox;
+	display: flex;
+	Align-items: center;
+	flex-wrap: wrap;
+}
diff --git a/lib/properties-order/__tests__/fixtures/properties-have-same-name-5.expected.css b/lib/properties-order/__tests__/fixtures/properties-have-same-name-5.expected.css
new file mode 100644
index 0000000..cbdbdf1
--- /dev/null
+++ b/lib/properties-order/__tests__/fixtures/properties-have-same-name-5.expected.css
@@ -0,0 +1,9 @@
+.header {
+	Align-items: center;
+	display: -webkit-box;
+	Display: -ms-flexbox;
+	display: flex;
+	flex-wrap: wrap;
+	Justify-content: space-between;
+	Padding-bottom: 20px;
+}
diff --git a/lib/properties-order/__tests__/properties-order.js b/lib/properties-order/__tests__/properties-order.js
index 10c5e3c..754c6b5 100644
--- a/lib/properties-order/__tests__/properties-order.js
+++ b/lib/properties-order/__tests__/properties-order.js
@@ -91,6 +91,24 @@ test('Should preserve order if properties have same name', () =>
 		__dirname
 	));
 
+test('Should preserve order if properties have same name (case insensitive)', () =>
+	runTest(
+		'properties-have-same-name-4',
+		{
+			'properties-order': ['position', 'z-index'],
+		},
+		__dirname
+	));
+
+test('Should preserve order if properties have same name (case insensitive)', () =>
+	runTest(
+		'properties-have-same-name-5',
+		{
+			'properties-order': 'alphabetical',
+		},
+		__dirname
+	));
+
 test(`Should not remove first comment in the rule if it's not on separate line (properties-order)`, () =>
 	runTest(
 		'first-comment-in-the-rule',
@@ -145,6 +163,16 @@ test('Should sort properties alphabetically', () =>
 		__dirname
 	));
 
+test('Should sort properties alphabetically regardless of case', () => {
+	runTest(
+		'properties-alphabetical-case-insensitive',
+		{
+			'properties-order': 'alphabetical',
+		},
+		__dirname
+	);
+});
+
 test('Should sort shorthand properties before their longhand versions', () =>
 	runTest(
 		'properties-alphabetical-shorthand',
diff --git a/lib/properties-order/sortNodeProperties.js b/lib/properties-order/sortNodeProperties.js
index 9c15667..e14b4bf 100644
--- a/lib/properties-order/sortNodeProperties.js
+++ b/lib/properties-order/sortNodeProperties.js
@@ -25,7 +25,7 @@ module.exports = function sortNodeProperties(node, { order, unspecifiedPropertie
 			isStandardSyntaxProperty(childNode.prop) &&
 			!isCustomProperty(childNode.prop)
 		) {
-			let unprefixedPropName = vendor.unprefixed(childNode.prop);
+			let unprefixedPropName = vendor.unprefixed(childNode.prop).toLowerCase();
 
 			// Hack to allow -moz-osx-font-smoothing to be understood
 			// just like -webkit-font-smoothing