In The New York Times, Jon Pareles wrote that Mama Said Knock You Out reestablished LL Cool J as "the most articulate of the homeboys", sounding "tougher and funnier" rapping about "crass materialism" and "simple pleasures". In Mark Cooper's review for Q, he wrote, "This 22-year-old veteran has lost neither his eye for everyday detail nor his sheer relish for words."Select magazine's Richard Cook said, "LL's stack of samples add the icing to a cake that is all dark, remorseless rhythm, a lo-fi drum beat shadowed by a crude bass rumble. It could be Jamaican dub they're making here, if it weren't for LL's slipper lip."Mama Said Knock You Out was voted the ninth best record of 1990 in the Pazz & Jop, an annual poll of American critics published by The Village Voice.
The album was included in Hip Hop Connection's The phat forty, a rundown of rap's greatest albums. "The LP's title track proved to be the single of the year and probably LL's best record since 'I'm Bad'," HHC said, "while 'Eat 'Em Up L Chill' and 'To Da Break Of Dawn' was [sic] the sound of Cool J getting his own back – and in style." In 1998, it was listed in The Source's 100 Best Rap Albums. In 2005, comedian Chris Rock listed it as the sixth greatest hip-hop album ever in a guest article for Rolling Stone.