Kane Williamson leads the side for his sixth T20 World Cup, a figure only bettered by Southee, who has been selected for his seventh. The tournament starts in the West Indies and United States in June.
Southee is New Zealand's leading wicket-taker in World Cup T20 internationals, with 29 wickets, four more than long-time teammate Trent Boult, who has been picked for his fifth World Cup in this format.
But Southee has been used sparingly in the T20 format by the Black Caps in recent times, with his 23 wickets in 2023 and 2024 coming at an average of 19.82. He was caned by the Australians in last outing, against Australia in Wellington in February, with his wicketless four overs costing 52 runs.
Selectors, head coach Gary Stead and Sam Wells, have opted to retain the 35-year-old, with young fast bowlers Will O'Rourke and Ben Sears missing out, though Sears has been named as the team's sole travelling reserve.
Southee and Boult are joined by Matt Henry and Lockie Ferguson as the squad's main pace bowlers.
Only two of the 15 chosen, Henry and Rachin Ravindra, have yet to play at that T20 World Cup level.
Adam Milne and Kylie Jamieson have been ruled out of the squad with ankle and back injuries respectively.
Opening batter Finn Allen, who missed the just-completed Black Caps' T20 tour of Pakistan due to a back injury, has been included in the squad.
Michael Bracewell, who led the team in Pakistan, is one of just four players from that series to be included in the squad. Most of the front-line Black Caps missed the tour due to injuries and other commitments.
The team has a strong spin lineup, with Bracewell, Ish Sodhi, Mitchell Santner, Glenn Phillips and Ravindra all selected.
Thirteen of the 15 players chosen played during the New Zealand's last tour to the West Indies in 2022, while six of them have also featured in the Caribbean Premier League T20 competition, a point emphasised by head coach Gary Stead.
"We expect the venues in the West Indies to offer quite varied conditions and feel we've selected a squad with the scope to adapt to those conditions,'' he said as the squad was announced in Auckland.
Stead said he was delighted to name Henry and Ravindra for their first T20 World Cup.
"Matt has worked exceptionally hard on his skills across the phases of a T20 game to come back into selection consideration," he said.
"Rachin has made every post a winner in the past 12 months and it was exciting to see him continue that trajectory over the summer in the T20 format against Australia."
Black Caps squad for T20 World Cup:
Kane Williamson (c)
Finn Allen
Trent Boult
Michael Bracewell
Mark Chapman
Devon Conway
Lockie Ferguson
Matt Henry
Daryl Mitchell
Jimmy Neesham
Glenn Phillips
Rachin Ravindra
Mitchell Santner
Ish Sodhi
Tim Southee
Ben Sears (travelling reserve)