[6] The race was won for the second consecutive year by Tadej Pogačar of UAE Team Emirates, becoming the youngest rider to win the Tour twice.

He first took the maillot jaune on stage 8, when he gained almost three and a half minutes on the other contenders after attacking on the penultimate climb of the Col de Romme.

[10] Aside from winning the maillot jaune, Pogačar also won the mountains and young rider classifications for the second successive year.

[16][17] Usually, only twenty-two teams would participate in the race, but for the 2021 season, the Union Cycliste Internationale is allowing the total number of riders to increase from the normal 176 to 184.

Their closest rivals were considered to be the trio of Geraint Thomas, Richard Carapaz and Richie Porte from Ineos Grenadiers.

[20] The other riders considered contenders for the general classification were Rigoberto Urán (EF Education–Nippo), Movistar Team duo Enric Mas and Miguel Ángel López, French riders Julian Alaphilippe (Deceuninck–Quick-Step), Guillaume Martin (Cofidis) and David Gaudu (Groupama–FDJ), 2020 Giro d'Italia champion Tao Geoghegan Hart (Ineos Grenadiers) and fellow podium finisher Wilco Kelderman (Bora–Hansgrohe).

[21] The sprinters considered favourites for the points classification and wins on the flat or hilly bunch sprint finishes were seven-time green jersey winner Peter Sagan (Bora–Hansgrohe), Caleb Ewan (Lotto–Soudal), Arnaud Démare (Groupama–FDJ), Tim Merlier and Mathieu van der Poel (Alpecin–Fenix), Wout van Aert (Team Jumbo–Visma), Sonny Colbrelli (Team Bahrain Victorious), Michael Matthews (Team BikeExchange) and Mark Cavendish, who was a late replacement for the injured defending champion Sam Bennett at Deceuninck–Quick-Step.

[22] The first stage featured a hilly course from Brest to Landerneau, with the finish situated atop the climb of Côte de la Fosse aux Loups.

A group of six broke away from the peloton, taking a lead of four minutes before Ide Schelling (Bora–Hansgrohe) attacked on the fourth climb of the day, the Côte de Stang ar Garront.

The rest of the break were caught before the intermediate sprint, where Schelling took maximum points before Caleb Ewan (Lotto–Soudal) outsprinted Peter Sagan (Bora–Hansgrohe) for second.

With 45 kilometres (28 mi) to go, time trial ace Tony Martin (Team Jumbo–Visma) was brought down by a spectator who was holding a sign greeting her grandparents for TV cameras facing forward, and therefore unaware of the incoming peloton.

Of the remaining ones that finished Schelling was caught with 27 kilometres (17 mi) left, but the KOM points he gained ensured that he wore the polka-dot jersey at the end of the day.

37 kilometres (23 mi) into the stage, a crash in the peloton brought down Geraint Thomas (Ineos Grenadiers) and Robert Gesink (Team Jumbo–Visma), with the latter eventually having to abandon the race.

Van der Poel escaped the crashes to retain the maillot jaune while Richard Carapaz (Ineos Grenadiers) also finished in the front group.

Van Moer would be caught near the finish, where Mark Cavendish (Deceuninck–Quick-Step) outsprinted Nacer Bouhanni (Arkéa–Samsic) to win his first Tour stage since 2016.

At the start of the stage, Roglič and Thomas were unable to follow the pace, eventually conceding more than 35 minutes and ending their chances for Tour victory.

Just before the second category-one climb of Col de Romme, the Team DSM duo of Søren Kragh Andersen and Tiesj Benoot attacked from the break.

In the peloton, van der Poel began to struggle on the Col de Romme as UAE Team Emirates started to set a furious pace.

Up front, on the final climb of Col de la Colombière, Woods started to fade and he was soon caught and dropped by Dylan Teuns (Team Bahrain Victorious).

Three riders eventually emerged as the strongest in the break, with Ben O'Connor (AG2R Citroën Team), Sergio Higuita (EF Education–Nippo), and Nairo Quintana (Arkéa–Samsic) were left at the front of the race as they began the final climb of Monteé de Tignes.

Hugo Houle (Astana–Premier Tech) and Tosh Van der Sande (Lotto–Soudal) established the day's main breakaway, but both riders were caught with around 36 kilometres (22 mi) to go.

[36] The race headed back into the mountains on the eleventh stage, with the riders tackling the Mont Ventoux twice before a descent into Malaucène.

At the bottom of the second ascent of the Ventoux, Kenny Elissonde (Trek–Segafredo) attacked the break while a chase group composed of Alaphilippe, van Aert, and Bauke Mollema (Trek–Segafredo) formed behind.

A 14-man break went off the front of the peloton, including Woods and Wout Poels (Team Bahrain Victorious) who were vying for the polka-dot jersey.

Near the top of the Port d'Envalira, Quintana attacked to take the Souvenir Henri Desgrange, given to the first rider across the highest point in the Tour.

On the last climb of the day, the Col de Beixalis, Sepp Kuss (Team Jumbo–Visma) launched his move 5 kilometres (3.1 mi) from the top.

[42] The seventeenth stage featured the first of two consecutive summit finishes as the riders tackled two first-category climbs and the hors catégorie Col de Portet in the final 62.5 kilometres (38.8 mi).

Two riders, Anthony Perez (Cofidis) and Dorian Godon (AG2R Citroën Team), proved themselves as the strongest from the break as the duo led by four minutes heading into the final climb, the Col du Portet.

At the top of the Tourmalet, only two riders were left at the front as David Gaudu (Groupama–FDJ) and Pierre Latour (Team TotalEnergies) led by around half a minute ahead of a chase group composed of Poels and Woods.

Meanwhile, Pogačar avoided taking any risks, eventually finishing with the eighth best time as he put himself on the cusp of winning his second successive Tour title.