Introduction: When sealer is adapted well to the root canal wall, there is less tendency for microleakage and strength of root canal is enhanced. Therefore, it is important for the sealer to possess good tubular penetration depth and adaptation to dentinal walls. Aim: To compare the effects of sonic activation of 5.25% Sodium Hypochlorite (NaOCl) and incorporation of Zinc Oxide (ZnO) nanoparticles in AH Plus sealer on tubular sealer penetration. Materials and Methods: Forty extracted human mandibular premolars with a single root canal were used for this invitro study from October 2019 to January 2020. All teeth were prepared upto F3 with Pro Taper Universal rotary system. Teeth were randomly divided into four groups of 10 teeth each. Group I (control) included teeth obturated using AH plus sealer, Group II: teeth obturated using AH plus sealer incorporated with ZnO nanoparticles, Group III: teeth prepared along with sonic activation of the irrigant followed by obturation using AH plus sealer and Group IV: teeth prepared along with sonic activation of the irrigants followed by obturation with AH plus sealer incorporated with ZnO nanoparticles. Irrigation was achieved with 5.25% sodium hypochlorite. The canals were dried and obturated using respective sealers and single gutta percha cones. After storage at 37°C and 100% humidity, the roots were split into two halves and sealer penetration in the dentinal tubules was examined by using scanning electron microscope. The values obtained were statistically analysed using One-way Analysis of Variance (ANOVA) with significant p-value less than 0.05. Results: In all the groups, sealer penetrated into the dentinal tubules. There was enhanced tubular sealer penetration (289.57±59.43 μm) after sonic activation of the irrigant (group 3) followed by that on addition of ZnO nanoparticles to the sealers (group 2) (278.21±71.24 μm) and the least was seen in the control group (group 1) (211.5±66.33 μm). The combined effect of both i.e., use of sonic activation of irrigant followed by obturation using modified sealer with gutta percha (group 4) (318.64±88.27 μm) showed greatest tubular sealer penetration depth. Conclusion: Incorporation of nanoparticles aids in improving sealer penetration which is further enhanced in case of sonic activation during irrigation.