Prince Bertil of Sweden, Bertil Gustaf Oskar Carl Eugén (February 28, 1912 – January 5, 1997), Duke of Hallandia, was the third son of King Gustav VI Adolf of Sweden and his first wife, Princess Margaret of Connaught. After his eldest brother Gustaf Adolf had died in 1947, leaving a less than one-year-old son, and every other heir to the throne had lost their right to it (due to untolerated marriages), it seemed likely that Bertil would one day become Regent.

For this reason, Bertil chose not to marry Welsh princess Lilian Davies, as that would violate his succession. However, his father lived long enough for Bertil's nephew Carl XVI Gustaf to achieve full age, and under the views of the new King, he was permitted to marry her, and did so on December 7, 1976. Still first in line to the throne (until the birth of Crown Prince Carl Philip in 1979), Bertil continued to be the King's deputy.

When the Act of Succession was changed in 1980, right to the throne was restricted to Carl XVI Gustaf and his descendants; however, a special addendum was made for Bertil's case, so that he became third (and, after the birth of Princess Madeleine in 1982, fourth) in line to the throne.

Prince Bertil was a very popular person domestically. He was fond of cars and a keen supporter and practitioner of various sports, notably Tennis and Boules.

See also: Swedish Royal Family