Objectives: This study aimed to investigate the effect of self-etch silane contamination on dentin bond strength to resin composite when using different adhesive systems. Methods: 40 flat occlusal dentin surfaces were prepared and randomly divided into 4 groups (n=10): group ER (Optibond FL); group SE (Clearfil SE bond); group SiER and group SiSE (Monobond Etch and Prime (MEP) followed by Optibond FL and Clearfil SE bond, respectively). Microtensile bond strength (µTBS) data was analyzed by two-way and one-way ANOVA followed by the post hoc Tukey honest test. The failure mode data was analyzed using Pearson Chi-square test. After undergoing different contamination procedures (distill water, phosphoric acid, and acidic primer with and without MEP contamination), 6 additional specimens were analyzed by scanning electron microscopy (SEM). Results: The two-way ANOVA indicated that the adhesive system and silane contamination significantly influenced the µTBS. µTBS (MPa) of all (ER 47.79±3.48; SiER 41.16±11; SE 39.77±3.16; SiSE 35.10±4.12) groups were significantly different from each other, except for the SE versus SiER group. The silane contamination significantly decreased the µTBS for both adhesive systems. Adhesive failure was the most common failure mode for the SiER, SE, and SiSE groups. Conclusions: Self-etch silane cross-contamination on dentin negatively impacted the µTBS of etch-and-rinse and self-etch adhesive systems. However, the etch-and-rinse adhesive system may be more effective in mitigating the effects of dentin contamination than the self-etch adhesive system.