Presented at the 2015 Aquarius/SAC-D Science Team MeetingIn this talk we discuss the Aquarius scatterometer calibration, starting with the instrument calibration. We examine the thermal environment of the Aquarius scatterometer, showing that it has very good temperature control. Next we assess the scatterometer stability using instrument-only methods and show it has been extremely stable to order 0.1 dB since mission start. Next we discuss the stability as quantified using external models and again show stability to order 0.1 dB in very good agreement with instrument-only methods. Then we discuss the methods used to absolutely calibrate Aquarius with respect to previous L-band radar systems. We show that Aquarius is relatively calibrated to order 0.1 dB for co-polarization channels and better than 0.2 dB for cross-polarization channels. Finally we discuss the calibration of the Aquarius wind speed product. We compare the Aquarius wind speed with radiometer wind speed products, other radar scatterometers, and numerical weather products. We show that the Aquarius wind speed product is on par with previous scatterometers in data quality.