The 1986 Tour de France was a cycling race held in France, from 4 July to 27 July. It was the 73rd running of the Tour de France. Greg LeMond of La Vie Claire won the race, ahead of his teammate Bernard Hinault. It was the first ever victory for a rider outside of Europe. Five-time Tour winner Hinault, who had won the year before with LeMond supporting him, had publicly pledged to ride in support of LeMond in 1986. Several attacks during the race cast doubt on the sincerity of his promise, leading to a rift between the two riders and the entire La Vie Claire team. The 1986 Tour de France is widely considered to be one of the most memorable in the history of the sport due to the battle between LeMond and Hinault.

Thierry Marie (Système U) took the first race leader's yellow jersey after winning the prologue time trial. The lead then moved to Alex Stieda (7-Eleven) after stage 1, only for Marie to recapture the lead after his team won the team time trial on stage 2. After short stints in the lead for Dominique Gaigne and Johan van der Velde, Jørgen V. Pedersen took the yellow jersey following a breakaway on stage 7 and retained the lead even after the first long time trial, won by Hinault. Stage 12 saw Hinault attack with Pedro Delgado (PDM–Ultima–Concorde), who won the stage, while Hinault moved into the lead. Hinault attacked again the following day, but was caught and dropped. LeMond gained back significant time, but still trailed his teammate by 40 seconds.

LeMond would move into the yellow jersey after stage 17, when Hinault fell behind on the climb of the Col d'Izoard. Stage 18 to Alpe d'Huez saw LeMond and Hinault finish hand-in-hand, with the latter winning the stage. LeMond's overall victory was sealed when Hinault was unable to overcome his deficit in the final time trial on stage 20. Urs Zimmermann (Carrera Jeans–Vagabond) finished third, and was the only rider who posed a threat to the La Vie Claire team, who also had the 4th placed rider in Andy Hampsten.

In the race's other classifications, Hinault won the mountains classification, Panasonic–Merckx–Agu rider Eric Vanderaerden the points classification, and La Vie Claire's Andrew Hampsten won the young rider classification. La Vie Claire finished at the head of the team classification by one hour 51 minutes, after placing four riders inside the final overall top-ten placings.

One of cycling's Grand Tours, the Tour consisted of 23 stages, beginning with a prologue in Boulogne-Billancourt and concluded on the Champs-Élysées in Paris. The race was organised by the Amaury Sport Organisation and was shown on television in 72 countries, with the total viewers estimated at one billion.

In June, 23 teams had requested to start in the 1986 Tour. The Tour organisers, Amaury Sport Organisation (ASO), accepted 21 applications, so a total of 21 teams participated in the 1986 Tour de France. The two teams whose application was denied were Skala-Skil and Miko. Each team sent a squad of ten riders, which meant that the race would start with a peloton of 210 cyclists, a record setting total. The ASO felt that 210 starters were too many and moved to reduce the size of the squads to eight riders each, but the teams protested, and the original number remained.

7-Eleven became the Tour's first team from the United States, with a squad consisting of eight Americans, one Canadian and one Mexican. Jim Ochowicz, 7-Eleven's founder and manager, met with the ASO and persuaded them to invite his team. In the Spring, the team withdrew from competition in Europe (missing the opportunity to become the first American team in the history of the Vuelta a España) due to the United States conflict with Libya, losing out on much needed competitive racing unavailable in the United States. Joop Zoetemelk, the reigning road world champion, started and finished his 16th Tour de France, a record that stood until it was tied by Sylvain Chavanel in 2018.

The teams entering the race were: