On January 23, 2018, Granderson signed a one-year, $5 million contract with the Toronto Blue Jays. On April 18, facing the Kansas City Royals, Granderson hit his ninth career grand slam. On April 24, Granderson hit his first walkoff home run since 2016 in a 10th inning victory against the Boston Red Sox. On May 15th, Granderson returned to Citi Field for the first time since he was traded to the Los Angeles Dodgers on August 18th, 2017 and went 1 for 4 with a single. On June 10, against the Baltimore Orioles, Granderson hit for a career high six RBIs with a home run, two doubles, a single and a walk. On June 25, while playing the Houston Astros, Granderson hit his eighth and ninth home runs of the season off of former teammate Justin Verlander to lead the Jays to victory.