Stochastic differential equations (SDEs) provide accessible mathematical models that combine deterministic and probabilistic components of dynamic behavior. This article is an overview of numerical solution methods for SDEs. The solutions are stochastic processes that represent diffusive dynamics, a common modeling assumption in many application areas. We include a description of fundamental numerical methods and the concepts of strong and weak convergence and order for SDE solvers. In addition, we briefly discuss the extension of SDE solvers to coupled systems driven by correlated noise.Under appropriate conditions, ordinary differential equations have a unique solution for each initial condition. SDEs, on the other hand, have solutions that are continuous-time stochastic processes. Methods for the computational solution of SDEs are based on techniques for ordinary differential equations, but adapted to account for stochastic dynamics.Some fundamental concepts from stochastic calculus are needed to describe the numerical methods. A set of random variables X t indexed by real numbers t ≥ 0 is called a continuous-time stochastic process. Each instance, or realization of the stochastic process is a choice from the random variable X t for each t, and is therefore a function of t.Any (deterministic) function f (t) can be trivially considered as a stochastic process, with variance V(f (t)) = 0. An archetypal example that is ubiquitous in models from physics, chemistry, and finance is the Wiener process W t , a continuous-time stochastic process with the following three properties: (1) For each t, the random variable W t is normally distributed with mean 0 and variance t.(2) For each t 1 < t 2 , the normal random variable W t 2 − W t 1 is independent of the random variable W t 1 , and in fact independent of 362