Peter Arrell Browne Widener II (June 25, 1895 – April 20, 1948) was a prominent American racehorse owner and breeder.

He was born in Long Branch, New Jersey, the elder child and only son of Joseph Early Widener (1871–1943) and his wife, Eleanor "Ella" Holmes Pancoast (1874–1929).

He grew up in Palm Beach, spending winters at Il Palmetto, the Treanor & Fatio-designed South End landmark built for his parents, and on the Widener family's Lynnewood Hall estate in Elkins Park, Pennsylvania.

Designed by Horace Trumbauer (house) and Jacques Greber (gardens), the 110-room Georgian-style mansion, along with its extensive and important art collection, was built by his grandfather, Peter Arrell Browne Widener.

While at Newport in July 1916, he made the papers for rescuing a daughter of prominent locals who had gone under in rough surf at Baileys Beach, and he held her in the water for 10 minutes until lifeguards arrived.

In 1917, he went to Washington, D.C., with his father, who persuaded the Surgeon General to admit him to the Army as a Private despite having flat feet and a suspect heart condition, caused by a childhood bout of pneumonia.

Not only did he become an owner of a large stable of racehorses in both the United States and in France, he took over Elmendorf Farm in Lexington, Kentucky, where his father stood Fair Play, his son Chance Shot and the imported stallion Sickle.

Also in 1954, the interest in Hialeah Park was sold to New Jersey property developer Eugene Mori, who had built the Garden State racetrack in Cherry Hill.

[8] When several members of European royalty visited Lynnewood Hall in person to view the Widener art collection, Peter A.B.

[10] Their daughter Ella Widener and her husband, Cortright Weatherill (1923–1988), owned Happy Hill Farm in Newtown Township, Delaware County, Pennsylvania.

At that point, her failing health led to her dispersing her racing stable and returning home to her apartment at the Lowell Hotel on East 63rd Street in New York City, where she died from cancer on February 3, 1970, aged 71.