We review the findings of theoretical studies in which Monte Carlo simulations, molecular dynamics, self-consistent field models or various analytical calculations were used to examine the self-assembly of nonionic amphiphilic polymers in solution. We also review results from similar studies that were aimed at investigating the interactions of these macromolecules with nonionic surfactants. The results of these studies are particularly useful in clarifying the morphology of the associated complexes. The findings also provide qualitative guidelines for tailoring the structure of the polymers/surfactants to yield the desired visco-elastic behavior in the host fluid. These guidelines facilitate the fabrication of complex fluids that find applications in enhanced oil recovery and as coatings, paints and films.