Abstract: A hair retainer 10 holds a ponytail of a user while selectively covering any desired portion of the ponytail. The preferred embodiment is a sleeve 12 having a top loop 14, which may include a tie 100, proximate one end near the head of a user to gather the hair and secure the ponytail. A bottom loop 16, secured to gather the opposite end of the sleeve, restrains the hair of the ponytail. The bottom loop 16 also grips the hair to position the bottom loop 16 and set the effective length 28 of the sleeve 12 relative to the ponytail. The tie 100 may comprise an elastic material. A plurality of gathers 18, 20, 34 may be distributed along the sleeve 12 around the circumference of the sleeve 12, positioning and blousing the sleeve 12 between gathers 18, 20, 34, and between the top and bottom loops 14, 16. The sleeve may assist in isolating the hair from contamination and damage in medical and industrial environments, and from interference with work by hair falling into a user's face.