diff --git a/X10D.Tests/src/Numerics/QuaternionTests.cs b/X10D.Tests/src/Numerics/QuaternionTests.cs
index c55ce9f..22e4fec 100644
--- a/X10D.Tests/src/Numerics/QuaternionTests.cs
+++ b/X10D.Tests/src/Numerics/QuaternionTests.cs
@@ -18,4 +18,22 @@ public class QuaternionTests
         Assert.AreEqual(axis, axisAngle.Axis);
         Assert.AreEqual(angle, axisAngle.Angle);
     }
+
+    [TestMethod]
+    public void ToVector3_ShouldReturnZeroVector_GivenIdentityQuaternion()
+    {
+        Assert.AreEqual(Vector3.Zero, Quaternion.Identity.ToVector3());
+    }
+
+    [TestMethod]
+    public void ToVector3_ShouldReturnVector_0_PI_0_GivenQuaternionCreatedFrom_PI_0_0()
+    {
+        Quaternion quaternion = Quaternion.CreateFromYawPitchRoll(MathF.PI, 0, 0);
+        var expected = new Vector3(0, MathF.PI, 0);
+        var actual = quaternion.ToVector3();
+        
+        Assert.AreEqual(expected.X, actual.X, 1e-5f);
+        Assert.AreEqual(expected.Y, actual.Y, 1e-5f);
+        Assert.AreEqual(expected.Z, actual.Z, 1e-5f);
+    }
 }
diff --git a/X10D/src/Numerics/QuaternionExtensions.cs b/X10D/src/Numerics/QuaternionExtensions.cs
index 2ad4fe4..ece66d1 100644
--- a/X10D/src/Numerics/QuaternionExtensions.cs
+++ b/X10D/src/Numerics/QuaternionExtensions.cs
@@ -64,9 +64,9 @@ public static class QuaternionExtensions
         float qz = normalized.Z;
         float qw = normalized.W;
 
-        float x = MathF.Atan2(2 * (qx * qw - qy * qz), 1 - 2 * (qx * qx + qz * qz));
-        float y = MathF.Asin(2 * (qx * qz + qy * qw));
-        float z = MathF.Atan2(2 * (qz * qw - qx * qy), 1 - 2 * (qy * qy + qz * qz));
-        return new Vector3(x, y, z);
+        float x = MathF.Asin(-2 * (qx * qy - qz * qw));
+        float y = MathF.Atan2(2 * (qy * qw + qx * qz), 1 - 2 * (qy * qy + qx * qx));
+        float z = MathF.Atan2(2 * (qx * qw + qy * qz), 1 - 2 * (qz * qz + qw * qw));
+        return new Vector3(-x, -y, -z);
     }
 }