Marshall opened the 2013 season with eight receptions for 104 receiving yards against the Cincinnati Bengals. He caught the late go-ahead touchdown pass in the fourth quarter of the 24–21 victory. In Week 2, against the Minnesota Vikings, he had seven receptions for 113 receiving yards and one touchdown in the 31–30 victory. In Week 6 against the New York Giants, Marshall stated he will wear green cleats to support his mental illness foundation and promote Mental Health Awareness Week; Marshall was expected to be fined, so he additionally said, "I'm going to get fined, and I'm going to match that, and we want to partner with a cancer-care ." Marshall was eventually fined $10,500 by the league. In Week 17, Marshall torched the Green Bay Packers by providing an early fourth quarter touchdown from quarterback Jay Cutler. Despite the effort, Marshall and the Bears lost the game 33–28, coming up short and missing the playoffs with a record of 8–8. Marshall ended the 2013 season with 100 receptions for 1,295 yards and a career-high 12 touchdown receptions, which is the third-highest in franchise history, behind Ken Kavanaugh and Dick Gordon's 13 in 1947 and 1970, respectively, and the most by a Bears player since Curtis Conway's 12 in 1995. It was also Marshall's fifth season with 100 or more receptions, which tied him with Wes Welker and Andre Johnson for the most in league history. Also, Marshall became the first player in Bears history to record multiple 100-reception seasons.