<p>This study investigates the dynamic behavior of nanoscale beams supported by a generalized elastic substrate using a new fractional thermoelastic framework. We developed a mathematical model for the nanobeam using the Euler–Bernoulli theory and incorporated Pasternak parameters to simulate the elastic support. The thermal relaxation effects were captured using a Fractional Moore–Gibson–Thompson (MGT) model, which provides a more nuanced approach than traditional thermoelastic theories. The governing equations were solved using the Laplace transform technique, from which we obtained the distributions of the temperature, bending moment, and transverse displacement. The numerical analysis of these results provides insight into how the fractional order parameter, nonlocal parameters, foundation properties, and various thermoelastic models influence the system response. The calculated beam deflection and dynamic behavior were validated by comparison with the existing literature, demonstrating excellent agreement with the established nonlocal thermoelastic nanobeam theories. This research not only advances the theoretical understanding of these systems but also has practical implications for the design and analysis of nanoscale devices in mechanical engineering and materials science.</p>