Pietro or Pier Giovanni Aliotti or Aleotti (died 1563) was an Italian bishop.
In 1532 he became Guardarobiere Pontificio and Maestro di Camera, initially for pope Clement VII and then for pope Julius III, before being made bishop of Forlì in 1551, a post he held until his death.
He also took part in the final documents produced by the Council of Trent and was one of the dedicatees of Bernardo Cappello's Rime.
Vasari reports that Michelangelo disliked him and nicknamed him 'Tantecose', since "he wanted to be involved in everything ... and everything depended on him".
Benvenuto Cellini also complained about him in his autobiography since he often urged him (on behalf of pope Clement VII) to complete unfinished commissions.