Two weeks before the Tour would start, there were only twelve teams interested in starting the Tour. The teams with Italian and Spanish sponsors were focussed on the Giro d'Italia and the Vuelta a España, and thought their cyclists were not able to compete in two grand tours in one year. This prevented Giovanni Battaglin, the winner of the mountains classification of 1979, from defending his title. Francesco Moser, who had left the 1980 Giro d'Italia injured, was the only Italian cyclist on the initial starting list, but he was not able to start, so the 1980 Tour was without Italian cyclists. One more team was added to the starting list, so the Tour 1980 started with thirteen teams, each with ten cyclists. The Boston-Mavic-Amis du Tour team was a combination of the Belgian Boston-Mavic team and French cyclists without a contract, combined into the "Amis du Tour" team.
The teams entering the race were:
The three most important favourites for the victory were Bernard Hinault, Joop Zoetemelk and Hennie Kuiper. Hinault was the winner of the two last editions, and had earlier that year won the 1980 Giro d'Italia. Zoetemelk, the runner-up of the last two editions, had switched teams to the Ti Raleigh team, which was considered one of the strongest teams. Kuiper had left the Ti Raleigh team and moved to the Peugeot team. The manager of that team, Maurice De Muer, had already managed Bernard Thévenet to a Tour win, and this made Kuiper confident.
The 1980 Tour de France started on 26 June, and had two rest days, in Saint Malo and Morzine.
Before the race, Hinault expressed dissatisfaction with the cobbled sections in stages five and six. In the 1979 Tour, Hinault had lost time in these sections, and he considered to organise a strike, Even though no strike was held, the route was still changed: after the fifth stage, tour organiser Felix Levitan decided to change the first 20 kilometres (12 mi) of the stage, to avoid the worst cobbled sections.
The 25 stages were won by riders from only four countries. In this year's edition of the Tour, the last rider in the General Classification after the consecutives mountain stages (16-19) was eliminated.
The prologue was won by Hinault, who remained the leader until the first team time trial, won by the Ti Raleigh team, whose Gerrie Knetemann became the new leader. In the next stage, Rudy Pevenage, Yvon Bertin and Pierre Bazzo escaped and won by ten minutes. Of those three, Bertin, a team mate of Hinault, was the best ranked, and became the new leader. When Bertin lost many minutes in the third stage, Pevenage became the new leader.
Hinault won the fourth stage, a time trial, but Pevenage remained leader. In the next stage, run in terrible weather, Hinault escaped together with Kuiper, won the stage and gained won 2 minutes on the rest. Many riders experienced tendinitis problems, including Hinault. The Ti Raleigh team won the team time trial in stage seven, and Hinault's problems were showing, as he could not do his part of the workload. Hinault spent the next few stages at the back of the peloton, talking with his team manager of the tour doctor.
In the time trial in stage 11, won by Zoetemelk, Hinault finished fifth, which was enough to become the new race leader, but with Zoetemelk only 21 seconds behind. Normally, Hinault was the better time trialist, so Zoetemelk's stage victory made him confident that he had the chance to win the Tour. On the evening before stage 13, which included mountains of the highest category, Hinault decided to withdraw. Zoetemelk, until that moment second in the general classification, became the new leader, but refused to wear the yellow jersey, in the tradition of Eddy Merckx who refused to don the yellow jersey in the 1971 Tour de France after Luis Ocaña left the race as leader.
In that thirteenth stage, Zoetemelk rode conservatively. He allowed Raymond Martin to escape, as he was no threat in the general classification, but kept close to Kuiper, who was his main rival for the overall victory. Zoetemelk remained leader after that stage, with Kuiper in second place, 1'10" behind him, while Martin climbed to third place. Zoetemelk kept following this defensive tactic for the rest of the race. In the sixteenth stage, one of Zoetemelk's team mates Johan van der Velde slipped and made Zoetemelk crash, injuring his thigh and arm. Zoetemelk quickly remounted and continued the race. Zoetemelk was able to get back to Kuiper, losing no time to him.
The fall in the sixteenth stage did affect Zoetemelk's performance in the seventeenth stage, as Zoetemelk had to let others go on the first climb. Helped by his team mates, he was able to stay close to his competitors, and the only riders that escaped were the ones that were no threat for the overall victory. In the eighteenth stage, Ludo Loos escaped and crossed all the cols first, finishing more than five minutes ahead of the rest. But Loos was already far behind in the general classification, and Zoetemelk finished in the second group, some minutes ahead of Kuiper, thus building his lead to more than five minutes.
Zoetemelk won the time trial in stage 20, and improved his margin to almost seven minutes, and thus won the 1980 Tour.
Shortly before the start of the Tour, it was announced that Dietrich Thurau had tested positive in his national championship. He was allowed to start the Tour while his B-sample was being tested. His B-sample gave a negative result, so he could continue the Tour.
On the day of the final time trial, when it was all but clear that Zoetemelk would be the winner, tour director Jacques Goddet wrote in the newspaper l'Équipe that the only thing that could keep Zoetemelk away from a Tour victory was the drug tests for anabolic products after the eighteenth stage. As the director, Goddet was well-informed about drug tests, and many journalists speculated that his comments meant that Zoetemelk's A-sample had returned positive. Zoetemelk had tested positive for anabolic products before, in the 1978 Tour de France, and was not happy about the insinuations. Tour co-director Félix Lévitan apologized for Goddet's choice of words.
At the end of the Tour, it was announced that all doping tests had returned negative.
There were several classifications in the 1980 Tour de France, four of them awarding jerseys to their leaders. The most important was the general classification, calculated by adding each cyclist's finishing times on each stage. The cyclist with the least accumulated time was the race leader, identified by the yellow jersey; the winner of this classification is considered the winner of the Tour. In the 1979 Tour de France, Gerhard Schönbacher and Philippe Tesnière had both been trying to finish last, which had received attention from the press. The Tour organisation wanted to the press to focus on the winners, so they added the rule that after the 14th to 20th stage, the last-ranked cyclist in the general classification would be removed.
Additionally, there was a points classification, where cyclists got points for finishing among the best in a stage finish, or in intermediate sprints. The cyclist with the most points lead the classification, and was identified with a green jersey.
There was also a mountains classification. The organisation had categorized some climbs as either hors catégorie, first, second, third, or fourth-category; points for this classification were won by the first cyclists that reached the top of these climbs first, with more points available for the higher-categorized climbs. The cyclist with the most points lead the classification, and was identified with a polkadot jersey.
Another classification was the young rider classification. This was decided the same way as the general classification, but only cyclists younger than 24 were eligible, and the leader wore a white jersey.
The fifth individual classification was the intermediate sprints classification. This classification had similar rules as the points classification, but only points were awarded on intermediate sprints. In 1980, this classification had no associated jersey.
A combination classification was also calculated; this was done by adding the points for the points classification, mountains classification, intermediate sprints classification and combativity award. A new competition was introduced in 1980, sponsored by the French television station TF1, therefore named "Grand Prix TF1". It was calculated from the results in the other classifications, and therefore seen as a successor of the combination classification that was calculated from 1968 to 1974. There was no jersey associated with the Grand Prix TF1. The Belgian Ludo Peeters won this classification.
For the team classification, the times of the best four cyclists per team on each stage were added; the leading team was the team with the lowest total time. The riders in the team that lead this classification wore yellow caps. There was also a team points classification. After each stage, the stage rankings of the best three cyclists per team were added, and the team with the least total lead this classification, and were identified by green caps.
After it was said that Zoetemelk only won because Hinault abandoned, Zoetemelk replied "Surely winning the Tour is a question of health and robustness? If Hinault does not have that health and robustness and I have, that makes me a valid winner." Hinault agreed to that, saying that it was the absent rider (Hinault) who is at fault, not the one who replaces him.
Hinault's knee problems were solved before the 1980 UCI Road World Championships, which he won.