Sarah Coyte grabbed 3-16 in her four overs and Ellyse Perry and Rene Farrell claimed two wickets each to restrict England to a modest 105-8 after Australia won the toss and elected to field.
Heather Knight's 29 off 24 balls and Sarah Taylor's 18 lifted England to 55-1 before seven wickets crashed for 46 runs against the steady Australian attack that was backed by smart fielding.
Australian captain Meg Lanning then smashed a 30-ball 44 studded with two sixes and four boundaries as the champions raced home with 29 deliveries to spare in a one-sided final.
Perry completed a remarkable all-round display with an unbeaten 31, having added 60 for the fourth wicket with Lanning.
England had won the inaugural women's World T20 competition at home in 2009 before Australia took the next two in the Caribbean in 2010 and Sri Lanka in 2012.
The match was played at the Sher-e-Bangla stadium ahead of the men's final between India and Sri Lanka at the same venue later on Sunday. – Sapa-AFP