Grey to brick-red overall, it is pale on the underside and has small but prominent triangular ears. Adults are between long with a tail, and weigh from .
African Pygmy Mice reach breeding age at about 6 to 8 weeks. Pregnancy lasts for around 20 days and the litter of about 3 young is born blind and hairless. Their eyes open after 2 weeks, and weaning is complete after 4 weeks. The lifespan is about 2 years, although individual specimens have been reported to live over 4 years in captivity.
The African Pygmy mouse has a unique trait. It stacks pebbles in front of its burrow. Overnight the pebbles gather dew and in the morning the pygmy mouse drinks the dew on the pebbles. After that it retires back to its den.