The 2018 Calder Cup playoffs of the American Hockey League began on April 19, 2018, with the playoff format that was introduced in 2016. The sixteen teams that qualified, eight from each conference, played best-of-five series in the division semifinals, with the playoffs continuing with best-of-seven series for the division finals, conference finals, and Calder Cup finals.

The Lehigh Valley Phantoms are a professional ice hockey team based in Allentown, Pennsylvania. The team competes in the American Hockey League (AHL) and serves as the primary development team for the Philadelphia Flyers of the National Hockey League.