Single phase fluid-stator heat transfer coefficients for a multi-stage rotor–stator spinning disc reactor are presented. The overall heat transfer coefficient is obtained by fitting experimentally obtained steady state outlet temperatures to an engineering model for the fluid flow inside the rotor–stator cavities. Heat transfer measurements are done for gap ratios of G =0.017 and 0.03, rotational Reynolds numbers of Re¿=0Re¿=0 to 12×105 and superposed dimensionless throughflow rates of Cw=211–421. From the overall heat transfer coefficient values for the fluid-stator Nusselt number Nus are obtained. For all values of Cw and G, Nus increases more than a factor of 4 by increasing Re¿Re¿ from 0 to 1.3×105. A throughflow dominated regime occurs for Re¿0.2×105Re¿>0.2×105, rotation dominates the heat transfer and no influence of Cw and G on Nus is observed. The thermal performance of the multi-stage rotor–stator spinning disc reactor, quantified in the volumetric overall heat transfer coefficient, increases from View the MathML sourceUovAVR-1=0.46±0.2 to 0.93±0.16 MW m-3 K-1 by increasing Re¿Re¿ from 0 to 4.5×105. The volumetric overall heat transfer coefficient of the multi-stage rotor–stator spinning disc reactor is more than a factor of 5 higher than in conventional tubular reactors.