- "I must be more tired than I thought..."
- — Mii, Tomodachi Life
Sleep occurs when a Mii is either taking a nap or sleeping for the night. When in the Mii's apartment when sleeping, a lullaby version of the apartment music will play.
At night, Miis are in their bed wearing Pajamas and, unlike naps, are in a deep sleep and cannot wake up. When they're sleeping at their house for the night, the player cannot call them, due to their deep, deep sleep. The player can draw on their face, or press the clear button to erase their face, leaving it blank (excluding the nose). The drawing applies only to the interference itself, and is not permanent on the mii.
The player can also view Mii's dreams. A thought bubble with a dream picture on it will appear. Clicking it will show the dream. When the dream is over, the Mii will wake up. If he/she is sleeping for the night, they will wake up, comment on their dream, and go back to sleep. If the player taps "Edit Mii" and changes the Mii's personality, they will wake up until the player leaves the apartment. They will often talk in their sleep.
Miis first slept in Tomodachi Collection, from around 7:00 PM to 10:00 AM. While the Mii is asleep, the player can draw on their face, or view their dreams, should they have any. If the player leaves their room, they may sometimes hear the Mii say things in their sleep.
Sleep is also used in Tomodachi Life, now sleeping between 6:00 AM and 10:00 AM. They fall asleep anywhere around this time and as long as they want depending on their mood or personality. Their sleep time fluctuates from night to night, but their sleep timing usually stays the same. For example, an energetic and exited Mii would stay up longer than a slow, calmer Mii.
- "Sleeping like a baby!"
- — In-Game Text, Miitopia
Sleep is also used in Miitopia, appearing as a status ailment in battles. When a Mii is asleep, they will gradually heal over the course of two turns, before waking up. An opposite of this ailment is Nightmare, which will deplete a Mii's HP instead of restore it.
Additonally, durring the player's time at an Inn or Campground, the player can briefly watch the Miis fall asleep when they are at an Inn, once they have first settled. At Campgrounds, one Mii will occasionally fall asleep if they are to keep watch, causing a monster to attack them.
- When married couples sleep at home, The male mii wears blue pajamas, while the female wears pink pajamas.