Ruthenium nanoparticles (RuNPs) attracted much attention in the last decade because of their potential applications in catalytic hydrogenation and oxidation reactions. The broad spectrum of applications of ruthenium in catalysis, notably together with its relatively low price, renders RuNPs an attractive alternative to platinum or rhodium. Many different additives were reported for the stabilization of RuNPs, in particular polymers and ionic liquids. Lately, many reports showed the effectiveness of RuNPs stabilization by coordinating molecules commonly used in organometallic chemistry such as amines, thiols, and alcohols. Very recently, the type of stabilizers was extended to more sophisticated ligands such as phosphorus, nitrogen and carbon donor ligands. In this mini-review, we will present an overview of the various ligands used for RuNPs, with an emphasis on phosphine ligand effects on the morphology and catalytic activity in hydrogenation reactions. Appendix gives a tabular overview of the key features of the RuNPs reviewed.