Madelyn or Madalyn is a feminine first name. Notable people with these names include:
Madelyn
Madelyn Clare (1894–1975), American actress
Madelyn Cline (born 1997), American actress
Madelyn Dunham (1922–2008), maternal grandmother of Barack Obama
Madelyn Pugh (1921–2011), American television writer who worked on the I Love Lucy television series Madelyn Renee (born 1955), American soprano formerly known as Madelyn Renée Monti Madelyn Vega, Puerto Rican journalist and attorney
Madalyn
Madalyn Aslan (born 1963), American-British writer, astrologer, and palmist
Madalyn Godby (born 1992), American track cyclist
Madalyn Murray O'Hair (1919–1995), American writer and activist
Madalyn Schiffel (born 1994), American soccer goalkeeper
Fictional characters
Madelyn "Maddie" Hayes, in the television series Moonlighting
Madelyn Stillwell, in the television series The Boys and The Boys Presents: Diabolical Madelyn Spaulding, a villain from Static Shock