Change color of the overflow button on ActionBar

You can change the image used for it using the following style declaration.

<style name="MyCustomTheme" parent="style/Theme.Holo">
    <item name="android:actionOverflowButtonStyle">@style/MyCustomTheme.OverFlow</item>
</style>

<style name="MyCustomTheme.OverFlow">
    <item name="android:src">@drawable/my_overflow_image</item>
</style>

And if you're using ActionBarSherlock, here's how to do it

<style name="MyCustomTheme" parent="style/Theme.Sherlock">
    <item name="android:actionOverflowButtonStyle">@style/MyCustomTheme.OverFlow</item>
    <item name="actionOverflowButtonStyle">@style/MyCustomTheme.OverFlow</item>
</style>

<style name="MyCustomTheme.OverFlow">
    <item name="android:src">@drawable/my_overflow_image</item>
</style>

XGouchet's answer is great, but just wanted to add that if you inherit from an existing style you'll get the standard padding, selected state, etc.

<style name="MyCustomTheme.OverFlow" parent="Widget.Sherlock.ActionButton.Overflow">
    <item name="android:src">@drawable/title_moreicon</item>
</style>

Some of these answers are serious overkill and some give limited results. The answer is much simpler. You can set it to whatever color you want, any time. Here:

toolbar.getOverflowIcon().setColorFilter(colorInt, PorterDuff.Mode.SRC_ATOP);