This study investigates the impact of restoration thickness (0.5 mm and 0.7 mm) on the fabrication accuracy of additively manufactured resin-based laminate veneers and examines how both restoration thickness and margin location influence margin quality. Utilizing partial-arch scans of prepared maxillary central incisors, 30 laminate veneers were produced (15 for each thickness) and analyzed for fabrication trueness and margin quality across various surfaces. The findings revealed that veneers with a 0.7 mm thickness exhibited significantly lower deviations in fabrication trueness across all evaluated surfaces, indicating higher accuracy. However, the quality of the margins was not influenced by the thickness of the restoration but was affected by the location, with labial margins showing the lowest quality. This suggests that while thicker (0.7 mm) veneers may require less adjustment due to higher fabrication trueness, attention should be given to the labial margins to address potential marginal integrity issues. This research highlights the importance of considering restoration thickness in the additive manufacturing of resin-based laminate veneers to optimize their fabrication accuracy and margin quality.