Tom Dumoulin (Dutch pronunciation: [ˈtɔm dymuˈlɛ̃ː]; born 11 November 1990) is a retired Dutch professional road bicycle racer who last rode for UCI WorldTeam Visma–Lease a Bike. He has won the Giro d'Italia and nine stages across the three Grand Tours, five medals in three different World Championships and two Olympic silver medals.

Known for his time-trialing ability, Dumoulin excelled in climbing and was viewed by many as a climbing specialist. At the 2015 Vuelta a España, Dumoulin had two stage victories and led the race into its final weekend, before losing four minutes on the penultimate stage and ultimately finished sixth overall. He led the 2016 Giro d'Italia during its opening week and won two stages at the 2016 Tour de France. His sole Grand Tour in 2017 was the Giro d'Italia, where he overcame stomach problems and a 53-second deficit entering the final stage to become the first Dutch winner of the race and the first Dutch Grand Tour winner since Joop Zoetemelk in 1980. Later that year, he became the first Dutch male to win the time trial at the UCI Road World Championships. In 2018, Dumoulin finished second overall at both the Giro d'Italia and the Tour de France.

Dumoulin missed the first half of the 2021 season after he took an indefinite break from cycling for personal reasons, ultimately making his return to the sport at the Tour de Suisse in June and winning his fourth Dutch National Time Trial Championships later that month. The following year, he announced that he would retire from the sport at the end of the 2022 season before retiring early on the 15th of August.