Pandl's in Bayside, which opened in 1968, will close after serving brunch on Sunday.
The restaurant is closing because it has been sold by the owner, Jimmy Pandl, a restaurant manager said.
Pandl's in Bayside was built by George Pandl, who sold it to Jimmy, his son, in 1987.
Jimmy also operates Eagan's on Water, Milwaukee Waterfront Deli and Pandl's Catering Complete.
The Pandl restaurants started in 1915 when Anna and John owned what is now called Jack Pandl's Original Whitefish Bay Inn. John Pandl died in 1932, and Anna eventually passed the business on to her sons George and Jack.
Today, Jack's son, John, is operating the Whitefish Bay restaurant.
The closing of Pandls in Bayside will not affect any of the other restaurants, the manager said.