WASHINGTON — Erin Moran, best known for her role as Joanie Cunningham on the television show “Happy Days,” has died. She was 56.

Moran played the younger sister of Ron Howard’s character, Richie Cunningham, on the 1970s show, which ran for 11 seasons.

Moran later continued the role in the spin off “Joanie Loves Chachi” with Scott Baio. The show aired on ABC for one season in 1983.

No word yet on the cause of death.