Smokey Robinson is being sued by 4 women who say they used to work for him … claiming he repeatedly sexually assaulted and raped them during their employment.

The suit was filed in Los Angeles Tuesday morning by four Jane Does claiming they used to work as housekeepers for the music star and his wife, Frances Gladney Robinson.

The 4 accusers — who say they overlapped while working for Smokey and Frances — claim they were assaulted multiple times … with the first alleged incident occurring in 2007.

The women claim Smokey would sometimes lay down a towel before allegedly forcing himself upon them so as not to make a mess of the bed linens. At least two of the victims claim he ejaculated inside them without protection.

They’re suing Smokey for sexual battery, assault, false imprisonment and gender violence … and they’re seeking at least $50 million in damages.

Smokey’s wife of 23 years is also included in the suit, though the women are clear she never engaged in any of the alleged sexual assaults or alleged rapes. Instead, they’re suing Frances because they say she knew about prior alleged sexual misconduct Smokey committed, and did nothing to prevent it from happening again.

They also claim Frances created a hostile work environment by using racially-charged epithets giving them arduous tasks and depriving them of meal and rest breaks.

We’ve reached out to Smokey and Frances … so far, no word back.