On September 13, 2018, Green had the first three-touchdown game of his professional career in Week 2 against the Baltimore Ravens, completing the hat-trick all in the first half, with each of his first three catches resulting in touchdowns in the 34–23 victory. In Week 4, against the Atlanta Falcons, with the Bengals trailing by five with only 12 seconds remaining, Dalton connected with Green on a 13-yard pass to give the Bengals the game-winning points. On October 7. in a 27–17 win over the Miami Dolphins in Week 5, Green caught six passes for 112 yards, setting a franchise record with his 32nd 100-yard receiving game. He suffered a toe injury in Week 8 against the Tampa Bay Buccaneers and missed the next three games. He returned in Week 13 against the Denver Broncos but re-injured the toe and was placed on season-ending injured reserve on December 5. He finished the 2018 season with 46 receptions for 694 receiving yards and six receiving touchdowns, ending his Pro Bowl streak at seven seasons. He was ranked 58th by his fellow players on the NFL Top 100 Players of 2019.