"...delivers a few pleasant surprises, including a smart story..."
— Adam Markovitz, Entertainment Weekly
"Although not bowling me over, Planet 51 is a jolly and good-looking animated feature in glorious 2-D."
— Roger Ebert, Chicago Sun-Times
"Lacking the crackling energy of Meatballs, Planet 51 never soars to the boundless heights, and skies, its animation so fantastically illustrates."
— Adam Keleman, Slant Magazine
"...a jellybean of a movie: bright, colorful, sugary, and with no real content."
— Tasha Robinson, Onion AV Club
"...a lame-brained toon that even kids will recognize as an insipid goof on sci-fi conventions."
— Todd McCarthy, Variety