The Women's 100 metre backstroke swimming events for the 2020 Summer Paralympics took place at the Tokyo Aquatics Centre from 25 August to 3 September 2021.
The final in this classification took place on 25 August 2021: The S6 category is for swimmers who have short stature, arm amputations, or some form of coordination problem on one side of their body.
The final in this classification took place on 30 August 2021: The S8 category is for swimmers who have a single amputation, or restrictive movement in their hip, knee and ankle joints.
The final in this classification took place on 27 August 2021: The S9 category is for swimmers who have joint restrictions in one leg, or double below-the-knee amputations.
The final in this classification took place on 2 September 2021: The S11 category is for swimmers who have severe visual impairments and have very low or no light perception, such as blindness, they are required to wear blackened goggles to compete.