The one-dimensional turbulence (ODT) model represents an efficient and novel multiscale approach to couple the processes of reaction, diffusion and turbulent transport. The principal ingredients of the model include a coupled deterministic solution for reaction and molecular transport and a stochastic prescription for turbulent transport. The model may be implemented as stand-alone for simple turbulent flows and admits various forms for the description of spatially developing and temporally developing flows. It also may be implemented within the context of a coupled multiscale solution using the ODTLES approach. This chapter outlines the model formulation, and applications of ODT using stand-alone solutions and ODTLES.