According to David McDonnell of the Mirror, the 23-year-old was charged with violent conduct after Burton's 1-1 draw with Peterborough.
The stopper was also ordered to pay a £2,500 fine following the incident with Peterborough forward Sammie Szmodics.
An FA statement read:
"An independent Regulatory Commission has suspended Kieran O'Hara for six matches with immediate effect and fined him £2,500 for a breach of FA Rule E3."
"The Burton Albion goalkeeper denied that his behaviour during the 44th minute of an EFL League One fixture against Peterborough United on Saturday 29 February 2020 amounted to violent and/or improper conduct but the charge was subsequently found proven."
"The Independent Regulatory Commission's written reasons will be published in due course."
Szmodics complained to referee Brett Huxtable, but the official didn't see the incident. However, Huxtable mentioned the allegation in his post-match report.
O'Hara's ban starts immediately, and he will miss Burton's game at Lincoln City in League One. He will not be available to play again until April.