Albert Leo "Dapper" O'Neil (April 12, 1920 – December 19, 2007) was an American politician who served as a socially conservative member of the Boston City Council for twenty-eight years. Prior to joining the council, he served on the Boston Licensing Board and was an operative for the Mayor of Boston James Michael Curley.

O'Neil graduated from Roxbury Memorial High School in 1937, and attended Suffolk University Law School, but left before graduating to serve in the United States Army during World War II. After the war, he graduated from the Staley School of the Spoken Word with a degree in oratory. He worked with a railroad company and was then employed by the state housing board.

In a 1978 interview, O'Neil explained that he got his nickname because his mother was very meticulous about how her children dressed, and where he grew up (the Roxbury neighborhood of Boston) "everybody had a nickname."

From 1948 to 1961, O'Neil ran for office five times, three times for state representative and once each for City Council and School Committee, losing all five races. He then chauffeured for Massachusetts gubernatorial candidate Endicott Peabody. After Peabody was elected Governor of Massachusetts in November 1962, he considered appointing O'Neil as his patronage secretary; however, O'Neil made public comments critical of the Massachusetts Democratic Party chairman, Gerard F. Doherty, and the job went to a Worcester attorney, William J. Luby. In October 1963, Peabody appointed O'Neil to the Boston Licensing Board. In 1967, O'Neil ran for Mayor of Boston, finishing eighth in the preliminary election with only 0.95% of the vote.

In January 1971, O'Neil was appointed to the Boston City Council after the resignation of Louise Day Hicks, who had been elected to the United States House of Representatives. He was subsequently re-elected fourteen times, each term lasting two years.

While on the council, O'Neil thrice ran for Suffolk County Sheriff. He lost the Democratic nomination to Thomas Eisenstadt in 1974, Dennis J. Kearney in 1978, and Robert Rufo in 1986.

In 1992, he was elected Council President after the death of Christopher A. Iannella.

In November 1999, O'Neil finished fifth (behind Francis Roache, Stephen J. Murphy, Peggy Davis-Mullen, Michael F. Flaherty) in an at-large race in which the top four make the council. In a story published in The Boston Globe after O'Neil's loss, Boston historian Thomas H. O'Connor wrote, "This is the last hurrah not merely for a man but for the politicking he represents." O'Connor went on to say that O'Neil's career endured "largely through the kinds of loyalties he built up over thirty years, from people for whom he'd done favors, and they'd never forget him, and they'd talk about him to their relatives. He built a political career on a system of local patronage."