The 1991 PBA First Conference Finals was the best-of-7 basketball championship series of the 1991 PBA First Conference, and the conclusion of the conference's playoffs. Ginebra San Miguel and the Shell Rimula X played for the 48th championship contested by the league. This series also serves as a rematch after Shell captured the championship in the same conference a year before when Ginebra (then known as the Añejo Rum 65ers) walked out of the playing court in the sixth and series-clinching game with Shell leading, 62-47 with 2:52 left in the second quarter.