The title compound, [Os₃(C₂₅H₂₂As₂)(CO)₁₀], contains a triangle of singly bonded Os atoms; both arsine ligands are equatorial with respect to the Os₃triangle. Each arsine-substituted Os atom bears one equatorial and two axial terminal carbonyl ligands, whereas the unsubstituted Os atom bears two equatorial and two axial terminal carbonyl ligands. The dihedral angles between the two benzene rings in the diphenylarsino groups are 67.42 (16) and 61.99 (16)°. In the crystal, molecules are linkedviaC—H...O hydrogen bonds into zigzag chains propagating along [010].