We have used X-ray reflectivity and Ii-area isotherms to study Langmuir films of a series of second- and third-generation monodendrons with hydrophobic C12H25 alkyl tails at the periphery and hydrophilic COOHCO2-CH3 or crown ether groups in the core. Both the limiting molecular areas and the layer thickness's sire consistent with a model in which the chains are directed nearly perpendicularly away from the water surface.