McGrath, 24, enjoyed a standout 2019-20 campaign which saw her take out the Andrea McCauley Medal for the second consecutive year, while leading South Australia on three occasions.
The allrounder also captained Australia A through their successful limited-overs series against India A in Queensland in December, notably hitting 97 from 90 deliveries and taking 3/48 with the ball in the opening match of the series.
McGrath returns to national contention after her Test debut in the 2017 Women's Ashes series, when she took three wickets and made 47 runs.
World Cup winner and Scorpions captain Megan Schutt has also retained her Cricket Australia contract for the 2020-21 season.
Schutt played an integral role in Australia’s World Cup triumph, when she took 4/18 in the final against India at the MCG, finishing as the tournament’s leading wicket-taker with 13.
Schutt, also ranked second and third in the world on the ICC T20I and ODI bowling rankings respectively, keeps her place as an important cog in the Australian women’s bowling attack.
At 27, she has captained the Statewide Super SA Scorpions for two seasons, and continues to admirably lead SA's best.
Cricket Australia contracted women’s players
Nicola Carey (Tasmania)
Ashleigh Gardner (New South Wales)
Rachael Haynes (New South Wales)
Alyssa Healy (New South Wales)
Jess Jonassen (Queensland)
Delissa Kimmince (Queensland)
Meg Lanning (Victoria)
Tahlia McGrath (South Australia)
Sophie Molineux (Victoria)
Beth Mooney (Queensland)
Ellyse Perry (Victoria)
Megan Schutt (South Australia)
Annabel Sutherland (Victoria)
Tayla Vlaeminck (Victoria)
Georgia Wareham (Victoria)