Lee, 48, vice chairman of Samsung Electronics and son of Samsung Group chairman Lee Kun-hee, would be grilled as a "suspect" in connection to bribery, prosecutors said.
"We have decided to question Lee tomorrow morning as a suspect," Lee Kyu-chul, spokesman for the special prosecutors, told reporters.
The scandal centers on Park's secret confidante Choi Soon-sil, who's accused of using her ties to Park to coerce top firms into "donating" tens of millions of dollars to two non-profit foundations, which Choi then used as her personal ATMs.
Samsung was the biggest contributor to the foundations, and is also accused separately of giving millions of euros to Choi to bankroll her daughter's equestrian training in Germany, in a bid to curry favor.
Prosecutors have for months questioned Lee and other senior Samsung officials.
The officials reportedly argued that although they were coerced to give money, they sought no favors in return, and thus the payments didn't constitute a bribe.