In this work, an efficient computational technique based on Lucas polynomials has been extended to approximately solve a certain class of fractional diffusion equations. Fractional order Lucas polynomials were used to represent the operational matrix of differentiation and integration. Subsequently, the fractional Klein–Gordon equation was reduced to a system of algebraic equations whose solution can be found through suitable algorithms such as Gauss elimination and Newton–Raphson methods. Based on the numerical results obtained, the proposed technique demonstrates a high level of efficiency and precision. © The Author(s), under exclusive licence to Shiraz University 2024.