In this article, the electrokinetic motion of a non-conductive particle immersed in an aqueous solution in a microchannel is studied; the particle is subjected to a lateral temperature gradient that is perpendicular to the direction of the applied electric field. Three-dimensional governing equations are solved numerically to simulate the motion of the particle. It is noticed that the particle undergoes lateral and rotational movements as well as a longitudinal motion. The lateral and rotational motions of the particle will be affected by a size of the particle, an applied external electric field and an initial magnitude of temperature gradient. The results show that the initial magnitude of the temperature gradient is the most significant factor. It was observed that by doubling the temperature difference, the particle travels 64 percent more in lateral direction. It also rotates 42 percent more while experiencing a doubled temperature difference. Another parameter that has been investigated is the magnitude of the electric field. By halving the magnitude of the applied electric field, the particle moves laterally 10 percent less for a constant longitudinal distance. Finally, it was discovered that the effect of size of the particle on its velocity is negligible. (C) 2018 Elsevier Ltd. All rights reserved.