The 2012 Tour de Suisse was the 76th running of the Tour de Suisse cycling stage race. It started on 9 June with an individual time trial in Lugano and ended on 17 June, in Sörenberg after nine stages. It was the 17th race of the 2012 UCI World Tour season.

The race was won by Movistar Team rider Rui Costa, who claimed the leader's yellow jersey after winning the second stage, and maintained the lead of the race until its conclusion holding off attacks from his rivals during the final two stages. Costa's winning margin over runner-up Fränk Schleck of RadioShack–Nissan – the 2010 winner – was fourteen seconds, and Omega Pharma–Quick-Step's Levi Leipheimer, the defending champion, completed the podium, seven seconds down on Schleck and twenty-one behind Costa.

In the race's other classifications, Ag2r–La Mondiale rider Matteo Montaguti won the mountains classification, Liquigas–Cannondale's Peter Sagan comfortably won the white jersey for the points classification, having won four stages during the race including the race-opening time trial stage. Astana finished at the head of the teams classification, winning two of the last three stages through Fredrik Kessiakoff's seventh stage time trial victory and Tanel Kangert winning the final stage.

As the Tour de Suisse was a UCI World Tour event, all eighteen UCI ProTeams were invited automatically and obligated to send a squad. Two other squads – SpiderTech–C10 and Team Type 1–Sanofi – were given wildcard places into the race, and as such, formed the event's 20-team peloton.

The twenty teams that competed in the race were:

For the third successive year, the race began with a short individual time trial in around the city of Lugano. Although starting and finishing at relatively the same height above sea level, the stage had a small hill – the western flank of Monte Brè – around midway through the 7.3 km (4.5 mi) parcours, being used in the race for the second year in succession, after then-world time trial champion Fabian Cancellara won the stage in a time of 9' 41" in 2011. Race organisers expected the best time for the stage to be four seconds slower than Cancellara's time from 2011, predicting a winning time of 9' 45" for the stage. After returning from injury in May's Bayern-Rundfahrt, Cancellara of RadioShack–Nissan was the undoubted favourite for the stage, having won the opening stage of the race on five separate occasions.

The first rider to depart the start in Lugano was SpiderTech–C10 rider Will Routley, who recorded a time of 11' 33" for the course. His stay at the top of the timesheets was short, as the next two riders – Team Type 1–Sanofi's Daniele Colli and Chris Anker Sørensen for Team Saxo Bank – went substantially quicker than his time. Julien Bérard lowered the benchmark to 10' 29" for Ag2r–La Mondiale, before former Lithuanian national champion Ignatas Konovalovas (Movistar Team) reduced the leading time further to 10' 24" before Team Sky rider Thomas Löfkvist pushed the leading time into the low 10-minute times, setting a time of 10' 05" for the course; his time was the best of the first wave of riders to start. Berard's team-mate Martin Elmiger was the first rider to record a time below ten minutes, beating Löfkvist's time by eleven seconds to set a time of 9' 54".

Elmiger held the top spot for all of fifteen minutes as Liquigas–Cannondale neo-pro Moreno Moser recorded the quickest time at the intermediate point 3 km (1.9 mi) into the stage, and maintained that form to the finish line, setting a time of 9' 50" to surpass the time of Elmiger by four seconds. The times of Moser and Elmiger remained untroubled for the majority of the following riders, and it was not until Cancellara took to the course, around two hours after they had completed their efforts, that their times came under significant pressure. Cancellara was nine seconds slower than Moser at the intermediate time-point, but paced the second half of the course more efficiently and was three seconds quicker at the end of the stage. As Cancellara was finishing, Sagan was starting the course and was six seconds quicker to the same time-point; Cancellara closed out the course quicker, but Sagan held on by four seconds to take the stage victory. Moser and Elmiger maintained third and fourth to the end, with the top five being rounded out by Astana rider Fredrik Kessiakoff.