Objective: This study aims to compare the length of resin tags of three different pit and fissure sealants using Scanning Electron Microscopy (SEM). Methods: An in vitro SEM analysis was conducted on extracted human molars treated with three different types of sealants: Sealant A (a conventional resin-based sealant), Sealant B (a polyacid-modified resin sealant), and Sealant C (a glass ionomer sealant). Ten teeth were selected for each group, with the occlusal surfaces prepared according to manufacturers' instructions before sealant application. After polymerization, the teeth were sectioned, and resin tag lengths were measured using SEM. Results: The resin tags for Sealant A were significantly longer than those of Sealants B and C. Sealant B demonstrated moderate tag lengths, whereas Sealant C showed the shortest tags. These lengths directly correlated with adhesive properties. Conclusion: The length of resin tags varied among the three sealants, possibly influencing their bond strength and efficacy. Sealant A may provide superior adhesion and caries protection, attributed to its longer resin tags.