Betty Aberlin (born Betty Kay Ageloff, December 30, 1942) is an American actress, poet, and writer. She is best known as Lady Aberlin on Mister Rogers' Neighborhood. Born Betty Kay Ageloff in New York City, Aberlin grew up in a Jewish family and attended public schools in Queens and Staten Island. She graduated from Bennington College, having studied art, modern dance, and literature with Howard Nemerov and Bernard Malamud. She made her debut at the Phoenix Theatre in 1954 in Sandhog, a folk-opera by Waldo Salt and Earl Robinson. Aberlin had a regular role as "Lady Aberlin" for 33 years on the children's television series Mister Rogers' Neighborhood. She also appeared on The Smothers Brothers Show (1975) and various TV spots. For a short period of time, using the name Betty Aberlin, she did a late night radio show on WYEP-FM in Pittsburgh, a station she helped found. The program featured jazz, comedy, and some spoken arts and poetry. The radio station was (and still is) a non-commercial, community supported station for progressive music, arts, and public affairs. Monthly station program guides of the time, the station's mission statement support this statement. She wrote and performed a sequence for The 90's, "Stop Me Before I Love Again", in a theme show on growing older, which aired on PBS.