Cole was elected to his first American League All-Star appearance (2nd overall). Cole did not appear in the game but finished the first half of the season with a 10–2 record with a 2.52 ERA and 177 strikeouts. He finished the season with 278 strikeouts, a new career high and good for second-most in the American League behind teammate Justin Verlander, a 15–5 record, and a 2.88 ERA, his best since the 2015 season. He led the majors in strikeouts per 9 innings (12.40). In Game 2 of the 2018 American League Division Series against the Cleveland Indians, Cole struck out 12 and walked none in seven innings in a 3–1 victory. Cole became the second pitcher to strikeout at least 12 hitters with no walks in the postseason, after Tom Seaver in the 1973 National League Championship Series.