Plasmonic photocatalysis represents the synergetic union of two active fields of research: plasmonic effects in illuminated metallic nanoparticles and catalytic effects in tailored metallic nanoparticles. Traditionally, metallic nanoparticles that excel for one application are limited for the other, but recent developments have shown that desirable catalytic behaviors, such as reduced activation barriers and improved product selectivity, derive from nonthermal behaviors uniquely produced by this synergy. After examining such findings, this review will address a specific debate that has recently surfaced: what is the relative degree of contributions of thermal and nonthermal effects in plasmonic photocatalysis? We demonstrate the importance of correctly accounting for thermal effects before characterizing nonthermal contributions. We show that another synergy occurs: these desirable nonthermal behaviors have a temperature dependence, and the resulting temperature-dependent reaction rates far exceed what can be explained from purely thermal effects alone. Thus, the synergy of plasmonic photocatalysis offers an exciting new contribution to the quest for efficient, selective, sustainable methods for chemical synthesis and energy conversion.