The Design Analysis Kit for Optimization and Terascale Applications (DAKOTA) is a software toolkit developed by engineers at Sandia National Laboratories to provide a flexible, extensible interface between analysis codes and iterative systems analysis methods. DAKOTA contains optimization algorithms using gradient and nongradient-based methods, parameter estimation with nonlinear least squares methods, uncertainty quantification with sampling, reliability, and stochastic finite element methods, and sensitivity/variance analysis with design of experiments and parameter study capabilities.