MonoBehaviour.OnApplicationQuit()

Description

Sent to all game objects before the application is quit.

In the editor this is called when the user stops playmode.

using UnityEngine;
using System.Collections;

public class ExampleClass : MonoBehaviour
{
    void OnApplicationQuit()
    {
        Debug.Log("Application ending after " + Time.time + " seconds");
    }
}

Note that iOS applications are usually suspended and do not quit. You should tick "Exit on Suspend" in Player settings for iOS builds to cause the game to quit and not suspend, otherwise you may not see this call. If "Exit on Suspend" is not ticked then you will see calls to OnApplicationPause instead.

Note: On Windows Store Apps and Windows Phone 8.1 there's no application quit event, consider using OnApplicationFocus event when focusStatus equals false.