Rui Alberto Faria da Costa ComIH (born 5 October 1986) is a Portuguese professional road bicycle racer, who rides for UCI WorldTeam EF Education–EasyPost. He is best known for winning the 2013 UCI Road World Championships in Tuscany, Italy (the first Portuguese rider to do so), three stages of the Tour de France in 2011 and 2013, one stage in the Vuelta a España in 2023, and the 2012, 2013 and 2014 editions of the Tour de Suisse, becoming the first cyclist to win the event for three consecutive years.

Born in Aguçadoura, Póvoa de Varzim, Costa started his career at Guilhabreu, a civil parish of Vila do Conde, then went to Santa Maria da Feira.

Costa became a professional cyclist at Benfica in 2007, and switched to Caisse d'Epargne in 2009. In 2009, Costa won the Four Days of Dunkirk, followed by a win on stage 8 of the 2010 Tour de Suisse.

In 2010, Costa was involved in an altercation with Carlos Barredo at the end of Stage 6 of the Tour de France, with Barredo removing his front wheel and attempting to club Costa with it before both riders lobbed blows at each other. Both were fined 300 francs for the incident.

At the Portuguese national championships in June 2010 Costa and his brother Mário tested positive for the banned substance methylhexanamine, which they claimed to have ingested inadvertently due to a tainted food supplement. Further testing proved that to be the case, and he re-signed with his former team, then known as Movistar Team, in April 2011 after five months of suspension.

In 2011, Costa performed well in the Vuelta a la Comunidad de Madrid: after second places in the first and third stages, he won the overall classification. Later that season, Costa rode away solo to win stage 8 of the Tour de France. Following his previous successes, Costa won the Grand Prix Cycliste de Montréal, sprinting away from a late breakaway, beating breakaway companion Pierrick Fédrigo. Both were chased by Philippe Gilbert, who made a late counter-attack, but came two seconds short.

In 2012, Costa finished third in the General classification of the Tour de Romandie. He won stage 2 in the Tour de Suisse, took the race's lead and successfully defended the yellow jersey through the Tour. He hung on to his 14-second overall lead over second-placed Fränk Schleck in the last stage, where Schleck attacked on the slopes of the Glaubenberg Pass. Schleck crested the climb with an advantage of a minute over Costa, but was reeled back in along the descent by the small group containing Costa. The pair finished the stage at the same time. He said after the important win: "I want to dedicate this to the team, because my teammates worked magnificently all week. I have no words to describe it." Costa headed to the Tour de France, slated to ride in support of his leader Alejandro Valverde, but crashes and incidents plagued Valverde, who still managed to grab a stage win and finished 20th overall. Costa placed higher than his captain in the general classification at 18th. He then participated in the GP Ouest-France, where he settled for second place of the French classic. He escaped on the last climb of the day with 5 kilometres (3.1 mi) to go, but Team Sky's Edvald Boasson Hagen passed him in the final kilometre, and Costa protected his second place as the surging peloton crossed the finish line on his heels. In September, he headed to the Canadian province of Quebec to take part in the two World Tour races held there. He took the third step of the podium in the Grand Prix Cycliste de Québec, winning the sprint of a group of 16 riders in hot pursuit of the two escapees, Simon Gerrans and Greg Van Avermaet, who finished four seconds ahead of Costa. Two days later, he aimed at defending his title in the Grand Prix Cycliste de Montréal, but finished eighth, once again with a 4-second deficit over the winner, Lars Petter Nordhaug. He concluded his season in China at the Tour of Beijing, scoring another top ten overall placing with ninth.

In 2013, Costa started the year by winning the Klasika Primavera and finishing third in the Tour de Romandie and also aimed to defend his Tour de Suisse title. He later successfully defended his title after winning stage seven, and then taking the yellow jersey from Mathias Frank after winning the final stage, a hill climb time trial. In the Tour de France, Costa left the Pyrenees inside the top ten. On stage 13, Costa lost close to ten minutes after going back to try to help his team leader, Valverde, who suffered a puncture. On stage 16, Costa ended up on a breakaway where he attacked on the last climb of the day, the Col de Manse before the final downhill to a solo finish in Gap. He was also awarded the combativity prize of that stage. A few days later, Costa won stage 19 after escaping from the lead group on the Col de la Croix Fry; he ended up with another solo finish in Le Grand-Bornand.