Both the women's semi-finals will be at the Sydney Cricket Ground.
The women's competition will run from 21 February to 8 march, while the men will start on 18 October and finish on 15 November.
ICC Chief Executive David Richardson praised Cricket Australia for a professional approach and insisted that the success of women's competition has forced for a stand-alone men's and women's events.
Eight cities will take up hosting duties for the WT20 tournament, with Sydney, Adelaide, Perth, Brisbane, Hobart, Canberra and Geelong joining Melbourne.
The MCG will host stand-alone finals for the men's and women's World Twenty20s after Cricket Australia promised to give both tournaments equal billing.More news: Eagles touch down in chilly Minneapolis ahead of Super Bowl
Hosting the women's final in Melbourne will nearly certainly see the largest attendance for a women's cricket match.
Sydney will host both women's semi-finals while the SCG and Adelaide Oval will host the men's semi-final matches.
"On behalf of Cricket Australia and the Local Organising Committee, I would like to sincerely thank Government at both Federal and State and Territory level, host cities, venues and State and Territory Cricket Associations for their exceptional support, which is so critical for delivering the best possible events in 2020".
The women's final will coincide with International Women's Day, with the world governing body, the International Cricket Council (ICC), hoping for a record attendance at a women's sporting event.
"ICC World T20 2020 provides a unique opportunity to engage the whole community and inspire the next generation to love cricket".More news: Jada Pinkett Smith To Host New Facebook Talk Show Series
Nick Hockley, the local organising committee chief, said the World T20 would be created to be more inclusive and accessible to encourage greater participation.
The men's competition will feature the world's top 16 teams, while the women's event will feature the top 10 teams.
Hockley added:"Major events of this scale are all about partnerships".
"I've been in the crowd watching people play out there in front of 90,000 people (at the MCG) and potentially the opportunity to be out there in the middle for that is really exciting", Australia women's captain Meg Lanning said.More news: Sharks' Burns helps Pacific Division win 2018 NHL All-Star tournament