STOCKHOLM—Prince Alexander, the newest member of Sweden’s royal family, was baptized Friday at Drottningholm Palace outside Stockholm.

About 150 guests attended the ceremony in the palace chapel for the baby boy, who was born in April.

He is the first child of Prince Carl Philip and Princess Sofia and is fifth in the line of succession.

The boy wore a white christening gown that has previously been worn by royal family members dating back to Prince Gustaf Adolf in 1906.

Carl Philip’s father, King Carl XVI Gustaf, is Sweden’s head of state, but his duties are ceremonial and he holds no political power.

The royal family is hugely popular in Sweden and the monarchy enjoys widespread support despite the egalitarianism that otherwise characterizes society in the Nordic country.