The 26-year-old Brown will be available for Vipers' Rachael Heyhoe Flint Trophy clash with Thunder on Friday and will be a part of their squad for matches up to and including the one against Northern Diamonds at Arundel on July 22 with fixtures against the Blaze and Western Storm in between.
Brown made her debut for Melbourne Renegades in the WBBL in 2016 before moving to Sydney Sixers for the 2021-22 season. It was in Sydney that she was coached by Vipers head coach Charlotte Edwards in the 2022-23 competition.
Edwards signed Brown to Southern Brave for £18,750 (A$35,875) in the inaugural women's Hundred draft, held in March for the upcoming season, which begins in August.
Brown was part of the Australia A squad which played three 50-over games and three T20s against England A on a tour running concurrently with the beginning of the Women's Ashes, as well as a three-day red-ball warm-up game against England ahead of last month's Test. She made her Australia A debut in 2018 against India, where she picked up figures of 2 for 16, and she has taken 20 wickets at an average of 28.25 in 24 matches.
Adam Carty, Vipers' regional director of women's cricket, said: "As a cricketer and a person, Maitlan has all the characteristics and attitude to be a Viper and we are delighted to bring her into the fold for what will be a pretty busy 50-over period for us.
"As a highly skilled, competitive bowling allrounder, we hope we'll provide an environment that will allow Maitlan to show her best side both on and off the pitch at a time when we'll be without a number of our senior players."
Three Vipers players - seamer Lauren Bell, offspinner Charlie Dean and batter Maia Bouchier - are part of England's T20 squad currently locked 1-1 with Australia in their three-match Ashes contest, with a squad yet to be named for the three ODIs which will complete the multi-format series.