Advanced composite structures made by using curved fiber path laminates allow the generation of spatially varying in-plane structural stiffness, which can tailor the in-plane stress distribution in a favorable way under external loads. The critical stress location can be shifted away from the weakest and imperfection regions for an imperfection-insensitive structure design. As a result, tow-steered laminates enable the improvement of the buckling response by tailoring both elastic and geometric stiffness matrices. Robotic arm-assisted Automated Fiber Placement (AFP) has been used for such advanced composite structure manufacturing. Narrow, thin, and uniform width prepreg slit-tapes are pulled from the spool and deposited on the mold under roller compaction and thermal heating. AFP enables prepreg tows or slit-tape placed with high accuracy of fiber path orientation, higher material deposition rates, and improved material utilization, thereby reducing manual layup errors, labor costs, and waste of raw materials. However, during the curved prepreg slit-tape deposition, a unique out-of-plane wrinkle deformation is generated compared to the conventional straight fiber path laminates. This wrinkle deformation is caused by the in-plane curvature-induced compression in the inner region of the deposited tape. The present work aims to understand wrinkle formation using both numerical analysis and experimental studies. The effect of prepreg slit-tape width and curvature on the wrinkle mode formation will be studied.