The purpose of this article is to introduce and review the capability and performance of the Stata item response theory (IRT) package that is available from Stata v.14, 2015. Using a simulated data set and a publicly available item response data set extracted from Programme of International Student Assessment, we review the IRT package from applied and methodological researchers' perspectives. After discussing the supported item response models and estimation methods implemented in the package, we demonstrate the accuracy of estimation compared to results from other typically used software packages. Other application features for differential item function analysis, scoring, and the package generating graphs are also reviewed.