This 2021 Workplace and Gender Relations Survey of Military Members–Reserve Component: Statistical Methodology Report (2021 WGRR) describes the statistical methodologies for the 2021 Workplace and Gender Relations Survey of Military Members (2021 WGR) Reserve component participants, fielded from December 9, 2021 to March 3, 2022. The report has eight sections. Section 1 defines statistical terminology in this report. Section 2 discusses the sample design and selection of the sample. Section 3 describes the design of experiments. Section 4 describes the weighting and variance estimation. Section 5 discusses the statistical tests used for the 2021 WGRR. Section 6 describes the calculation of contact, cooperation, and response rates for the full sample and population subgroups. Section 7 discusses the results of the experiments. Section 8 discusses nonresponse bias.