A new bulky silazido ligand, –N(SiHMe₂)Dipp (Dipp = C₆H₃-2,6-iPr₂), supports planar, three-coordinate homoleptic rare earth complexes Ln{N(SiHMe₂)Dipp}₃ (Ln = Sc, Y, and Lu), each containing three secondary Ln↼HSi interactions and one agostic CH bond. Y{N(SiHMe₂)Dipp}₃ and acetophenone react via hydrosilylation, rather than by insertion into the Y–N bond or by enolate formation.