The current global antibiotic resistance crisis has generated a resurgence of interest in phage therapy in Western medicine. In parallel, recent findings have shown how tightly bacterial quorum sensing interacts with phages. In this work, we study the effects of having a functional QS system on the susceptibility to temperate bacteriophages in P. aeruginosa. We found both, experimentally and using mathematical models, that the lysogenic bacteriophages select QS-proficient phenotypes as compared to the QS-deficient mutants during competition experiments with mixed strain populations in vitro and in vivo in Galleria mellonella. We show that this phenomenon restricts social cheating, and we propose that temperate phages may constitute an important selective pressure toward the conservation of bacterial QS. We further evaluate the potential consequences of our results in regard to phage therapy.