The 37-year-old Sangakkara joined India's Virender Sehwag as the only two players to be named as Wisden's Leading Cricketer in the World for a second occasion.
The selection is based on a player's class and form shown in all cricket during the calendar year, and is guided by statistics.
Kumar Sangakkara was Man of the Match as Sri Lanka beat India in the final of the World Twenty20, and finished with 2,868 runs in all formats, breaking Ricky Ponting's record for a calendar year.
At the 2015 World Cup, Sangakkara confirmed his standing by scoring an unprecedented four successive centuries, Wisden highlighting his achievements said.
Editor of Wisden Almanack Lawrence Booth commented "Choosing Sangakkara just felt natural. And his four consecutive hundreds at the World Cup confirmed we'd chosen the right man. We'll miss him when he's gone."