Late goals from Thomas Ince and Kevin Phillips earned Blackpool a third straight away win and lifted them into the play-off places.
Jon Stead gave Bristol City a first-half lead with his first goal of the season but Ince equalised thanks to a deflected free-kick.
Ince claimed his second of the game with six minutes left before Kevin Phillips netted a third.
City, without a win in six matches, are just three points above the drop zone.
Stead opened the scoring when he turned his man inside the area and placed a left-footed shot into the bottom corner.
Blackpool were level when Phillips won a free-kick in a dangerous position and Ince beat David James.
The former England goalkeeper was beaten again when Ince tapped in at the far post from Brett Ormerod's left-wing cross.
Ormerod was also involved in the third goal three minutes later, playing the ball out to Stephen Crainey before Phillips knocked home from six yards.