Zion garnered praise from the ratings and reviews of music critics. At Christian Broadcasting Network, Hannah Goodwyn rated the album four-and-a-half spins, writing that "The music, the lyrics, the movement, it all comes together in Zion." Matt Conner of CCM Magazine rated the album four stars, stating that this is yet "Another strong United release." Andrea Hunter of Worship Leader rated the album four-and-a-half stars, writing that listeners will "find songs across generations and traditions to honor God and transform hearts." At Cross Rhythms, Tony Cummings rated the album a perfect ten squares, saying that the band "have released a peach of an album". In addition, Cross Rhythms' Stephen Curry rated the album a perfect ten squares, indicating how the release contains "a variety of sounds and moments of creativity", and the band "should be applauded for their subtle but brave changes in musical direction." Ryan Barbee of Jesus Freak Hideout rated the album four-and-a-half stars, stating that he takes his hat off due "to your art." According to Scott Fryberger of Jesus Freak Hideout, who rated the album four stars, says that this is "the best album United has ever released". Jonathan Andre of Indie Vision Music rated the album four stars, writing that the release "is full of lyrically rich themes and messages against the backdrop of electronic music that presents a unique way of creating worship music". At New Release Tuesday, Mary Burklin rated the album four-and-a-half stars, stating that "a richly textured release that manages to achieve an intimate, organic feel despite the band's massive international reach." David Jeffries of AllMusic rated the album three-and-a-half stars, writing that the release is "just a touch overstuffed." At Louder Than the Music, Jono Davies rated the album a perfect five stars, remarking how the release is "Epic, Brilliant and Original." Emily Kjonaas of Christian Music Zine rated the album three-and-a-half stars, saying that "this is a great worship album that will help you keep your focus on Christ."
Zion is Hillsong United's most successful album to date, with 34,100 units being sold in its first week. It sold 25% more than Aftermath, allowing it to debut at number five on the US Billboard 200. The album debuted at number one on the Australian ARIA Albums Chart.