In this study, the problem of thermoelastic interaction in a microscale beam subjected to a moving heat source in the context of Green and Naghdi theory type III is investigated. The both ends of the microscale beam are clamped and thermally isolated. The basic equations have been written in the form of a vector-matrix differential equation in the Laplace transform domain, which is then solved by an eigenvalue approach. The analytical solution in the Laplace domain is obtained for lateral deflection, displacement, temperature, and stress. The effects of moving heat source speed are analyzed. The resulting quantities are depicted graphically.