In this paper, a unified framework is developed to describe acceleration methods for the iterative convergence of neutron transport problems. The framework is that of a two-level multigrid algorithm. All widely-known transport acceleration methods not based on direct matrix manipulations (i.e., SOR or Chebyschev acceleration) can be described within this framework. Our presentation provides a way of understanding older methods within a unified theory, and it easily allows for the development of new methods.