Self-consistent-field (SCF) calculations are presented of a planar grafted polymer layer that interacts either with free polymer chains or with another grafted layer. Three different systems are studied. The first is a grafted polymer layer immersed in a polymer solution. The interaction between grafted and free polymer can significantly influence the grafted polymer volume fraction profile. For grafted chains that are strongly stretched the lattice calculations are compared with the theory of Zhulina, Borisov, and Brombacher (Macromolecules 1991, 24, 4679). Good agreement is found when the free chain length is far smaller than the grafted chain length. The scaling behavior of the penetration of free polymer into the grafted layer is also studied for this system. In the second type of system the interaction between two grafted layers in the absence of free polymer is considered. The lattice calculations agree well with the theory of Zhulina et al. In the third system free polymer is present between the interacting grafted layers. If this free polymer has a small chain length, its main effect on the interaction free energy is the compression of the free grafted layers, and only repulsion is found. However, for larger chain lengths a depletion attraction between the grafted layers appears.