This review describes some of the fascinating advances in the field of rhodium nanoparticle (NP) catalysis that have emerged in recent years. The examples described are categorized according to the research approach applied, involving either direct engineering of the NP core (size/shape control) or manipulating the NP via a stabilizer and/or solvent. Consequently, both surface-immobilized heterogeneous Rh NP and solvent dispersed Rh NP catalysts are included. The interplay between relevant parameters and the catalytic properties of Rh NPs are discussed, with a focus on design, function, and mechanisms. Rh NP-based multifunctional systems are also described. The approaches used to probe Rh NP catalysts at a molecular level and possible future research trends are highlighted.