Purpose: The goals are to develop a computer system that performs an automatic and comprehensive plan quality check (QC) according to institutional guidelines, QUANTEC, and RTOG standards, and to standardize and streamline the evaluation, approval, and review of radiotherapy treatment plans. Methods: A computer software program (and backend database) was developed to automatically 1) read the plan data directly from the TPS, 2) process data, 3) match ROI names, 4) compute DVHs, 5) compute plan quality metrics from the DVHs, 6) evaluate the metrics against the QC rules, and 7) create a report. A rule defines a plan metric that should be satisfied, e.g. V95%>95% for PTV. Rules are organized in groups, and multiple groups are defined for each disease site corresponding to different prescriptions or treatment modalities. On‐the‐fly management of groups and rules is implemented to allow creating, editing, copying, and deleting. The tool can create new isodose structures and composite ROIs on‐the‐fly to support comprehensive yet flexible rules. The tool supports a number of plan quality metrics based on DVH or volumetric data and checks complex metrics including hot spots and conformity ratio. OARs that are not covered by the rules are automatically checked against standard OAR tolerances defined in QUANTEC or RTOG protocols. The report is presented to users with multiple tabulated forms containing color coded results and references. Results: This plan QC tool has been successfully tested. The computed DVH and plan quality metrics were verified to be within 0.5% of the TPS computation. It takes less than 1 minute to load data from a TPS, check all the rules, and generate a report, demonstrating the efficiency of this tool. Conclusion: This software program efficiently checks plan quality and is useful for assisting dosimetrists/physicists in treatment planning and physicians in plan evaluation, approval, and chart review.