Increasing the temperature gradient across thermoelectric (TE) devices improves the TE power output significantly. However, enhanced thermal gradients lead to high thermal stresses and these stresses must be taken into consideration in the design process to develop TE systems with enhanced thermal reliability. The shape of TE leg plays a major role on the performance of these systems. Conventional prismatic TE leg structure has been the preferred leg topology commonly utilized in TE devices due to its simplicity and high thermoelectric performance. Other leg topologies have also been considered in the literature to quantify their effects on TE performance. This current study investigates the thermal reliability of a several TE leg topologies such as trapezoidal leg, butterfly leg, vertical and horizontal cross-shaped leg, X-leg, Y-leg, I-leg according to the construction of each shape. 3D numerical model is presented to quantify the Von Mises stresses of these configurations and compared to conventional rectangular TE leg shape. The vertical cross-shaped and butterfly configurations generate 36% and 27% TE power higher than the conventional rectangular TE leg, respectively. On the other hand, the conventional TE leg has the lowest thermal stress compared to other TE leg topologies.