The feature adjusts your phone's display so that it will be easier on your eyes before sleep. In the evenings, it automatically shifts your phone's display light to a subtly warmer hue, rather than the bright blue glowing light that's been found to disrupt people's natural circadian rhythms before falling asleep.
But it's only available on certain devices, and there are a number of options to consider. Here's what you need to know.
Before you can activate Night Shift, you have to update your phone's operating system to the latest version, iOS 9.3.
Then head to Settings, select Display & Brightness, and then select Night Shift.
Your phone will automatically enable the feature based on sunrise and sunset times in your current location, or you can manually schedule the time you want the warm hue to activate, if you prefer.
You can also adjust the color temperature to your liking on a sliding scale.
Those who have older devices -- without the 64-bit processor that the feature needs to work -- are out of luck.
What about Android users who are tired of tossing and turning at night? There are a number of apps that promise to do the same thing for Android devices.
Twilight, NightOwl, Bluelight Filter, EyeFilter and others offer an array of features to adapt your screen's display light to warmer, more sleep-friendly tones in the nighttime hours.
Users can head to Google Play to download one of the apps.
Of course, there's also a non-technological solution for those so inclined: You could just turn the phone off well before bedtime.