Portugal's first participation in the Summer Olympic Games took place at the 1912 Summer Olympics in Stockholm, Sweden. The nation was represented by a delegation of six competitors, who took part in three sports but failed to win a medal. The Portuguese debut participation was marked by the death of flag bearer Francisco Lázaro, who succumbed to electrolytic imbalance after the marathon race.
4 athletes represented Portugal in the nation's Olympic debut. Lázaro collapsed during the marathon due to his use of wax to prevent sweating; he died the next morning.
Ranks given are within that athlete's heat for running events.
A single fencer represented Portugal in that nation's Olympic debut. Fernando Correia was disqualified in the first round of the épée competition.
Portugal's Olympic debut included two wrestlers. Both wrestlers lost their first bout, won their second, and lost their third to be eliminated.