diff --git a/docs/api/math/Quaternion.html b/docs/api/math/Quaternion.html
index 88200ecabab9c50bf4e8f22b19b726f9c68692c4..a9c4b114e0f7b096fae86e3a8aeb45fc7e59fe44 100644
--- a/docs/api/math/Quaternion.html
+++ b/docs/api/math/Quaternion.html
@@ -59,13 +59,17 @@
 
 		<h2>Methods</h2>
 
+		<h3>[method:Float angleTo]( [param:Quaternion q] )</h3>
+		<p>
+			Returns the angle between this quaternion and quaternion [page:Quaternion q] in radians.
+		</p>
+
 		<h3>[method:Quaternion clone]()</h3>
 		<p>
 			Creates a new Quaternion with identical [page:.x x], [page:.y y],
 			[page:.z z] and [page:.w w] properties to this one.
 		</p>
 
-
 		<h3>[method:Quaternion conjugate]()</h3>
 		<p>
 		Returns the rotational conjugate of this quaternion. The conjugate of a quaternion
diff --git a/src/math/Quaternion.js b/src/math/Quaternion.js
index 0d998926b8a1c562bc9c3735b51216b173015e5d..a437ef1e76da3b26e0190bbb0ea592138a7d8e5b 100644
--- a/src/math/Quaternion.js
+++ b/src/math/Quaternion.js
@@ -393,6 +393,12 @@ Object.assign( Quaternion.prototype, {
 
 	}(),
 
+	angleTo: function ( q ) {
+
+		return 2 * Math.acos( Math.abs( this.dot( q ) ) );
+
+	},
+
 	inverse: function () {
 
 		// quaternion is assumed to have unit length
diff --git a/test/unit/src/math/Quaternion.tests.js b/test/unit/src/math/Quaternion.tests.js
index 8ad4faabc7589dcf2177c6ea849bc1bdcf7b0ff5..85dddf8278f8e5aa714944c0537ecc25fffcfde3 100644
--- a/test/unit/src/math/Quaternion.tests.js
+++ b/test/unit/src/math/Quaternion.tests.js
@@ -391,6 +391,20 @@ export default QUnit.module( 'Maths', () => {
 
 		} );
 
+		QUnit.test( "angleTo", ( assert ) => {
+
+			var a = new Quaternion();
+			var b = new Quaternion().setFromEuler( new Euler( 0, Math.PI, 0 ) );
+			var c = new Quaternion().setFromEuler( new Euler( 0, Math.PI * 2, 0 ) );
+			var d = new Quaternion().setFromEuler( new Euler( 1, 1, 1 ) );
+
+			assert.ok( a.angleTo( a ) <= eps, "Passed!" );
+			assert.ok( ( a.angleTo( b ) - Math.PI ) <= eps, "Passed!" );
+			assert.ok( ( a.angleTo( c ) - ( Math.PI * 2 ) ) <= eps, "Passed!" );
+			assert.ok( ( a.angleTo( d ) - ( 1.939087528822506 ) ) <= eps, "Passed!" );
+
+		} );
+
 		QUnit.test( "inverse/conjugate", ( assert ) => {
 
 			var a = new Quaternion( x, y, z, w );