In this research, the mutual influence of the mechanical properties and geometric parameters on thermal stress distribution in symmetric composite plates with a quasi-rectangular hole subjected to uniform heat flux is examined analytically using the complex variable technique. The analytical solution is obtained based on the thermo-elastic theory and the Lekhnitskii’s method. Furthermore, by employing a suitable mapping function, the solution of symmetric laminates containing a circular hole is extended to the quasi-rectangular hole. The effect of important parameters including the stacking sequence of laminates, the angular position, the bluntness, and the aspect ratio of the hole and the flux angle in the stacking sequence of [45/−45]s for composite materials are examined in relation to the thermal stress distribution. The thermal insulated state and Neumann boundary conditions at the hole edge are taken into account. It is found out that the hole rotation angles and heat flux angle play key roles in obtaining the optimum thermal stress distribution around the hole. The present analytical method can well investigate the interaction of effective parameters on symmetric multilayer composites under heat flux.