21 received mildly positive reviews from
music critics. Andy Kellman of
AllMusic gave it an "Album Pick" title, praising the production throughout and Omarion for putting more input as a songwriter and performer, saying that he "truly surpassed his status as the former member of a boy band." Mark Edward Nero of
About.com was also mixed towards the album, praising the first two singles but found the other tracks above-average at best, in terms of production and vocal quality that "range from average ("Obsession," Made For TV,") to fair ("Midnight," "Beg For It")." He concluded with: "Although O's taken a step forward in establishing himself as an adult solo artist, he still hasn't completely arrived yet. But at only 21 years of age, he's still got plenty of room to grow." ==Commercial performance==