This paper presents results from an interlaboratory comparison of S-parameter measurements where the measurement uncertainty has been evaluated using the dynamic uncertainty option within the PNA vector network analyzer (VNA) from Keysight Technologies. The same devices were measured at two different laboratories (NPL, UK, and the University of Surrey, UK), both using a VNA with the dynamic uncertainty option. Several one- and two-port devices were chosen with a range of different values of reflection and transmission coefficients. The uncertainty of the S-parameter measurements has been evaluated for two different calibration methods (short-open-load-reciprocal and electronic calibration) and these are also reported. The investigation was carried out over the frequency range 100 MHz to 26 GHz which covers many of today’s RF and microwave applications.