Sharapova, ranked No. 4 in the world among women players, has been without a coach since August.
She said on her website she would make her first competitive appearance under Groeneveld's tutelage at the Brisbane International next month.
"We've been working together since I got back on the court and, after seeing him on the opposing side for so many years, I'm excited to have him become a part of my team," Sharapova wrote.
Groeneveld, 48, has worked with a number of top women players, Russia's R-Sport said Saturday.
Sharapova has been sidelined by a shoulder injury for the past several weeks, but plans to compete in three exhibition matches along with the Brisbane tournament in the near future, R-Sport said.