Betty Aberlin (born December 30, 1942) is an American actress, poet, and writer.
Born Betty Kay Ageloff in New York City, Aberlin had a regular role on the children's television series Mister Rogers' Neighborhood. She also appeared on The Smothers Brothers Show (1975) and various TV spots. Her film work includes roles in the Kevin Smith films Dogma, Jersey Girl, and Red State. She had a supporting role as "Cheryl" in the Joseph Papp production of Cryer & Ford's "I'm Getting My Act Together and Taking it on the Road" at The New York Shakespeare Festival's Public Theatre in New York.
As a contributor to the literary website "Fresh Yarn," Aberlin's essay, The Blonding of America, was published in 2005. She has also published a collection of poems, The White Pages Poems, as a companion to A Book of Strife, in the Form of the Diary of an Old Soul, an 1880 collection of poems by George MacDonald.
Musician Jonathan Coulton wrote the song "Lady Aberlin's Muumuu" about Aberlin's Mister Rogers character.