Attention Deficiency and Hyperactivity Disorder (ADHD), as a predictor of injuries in motorcyclists, affects the risky behavior. Since there was no pre-established conceptual model, this study aimed at exploring a conceptual model. Following this model, the Structural Equation Modeling (SEM) was utilized to find the predictors of Motorcycle Riding Behavior (MRB), as well as the mediators and moderators of ADHD-MRB relationship. In the current cross-sectional study, 340 motorcyclists in Bukan city, Iran, were recruited through a randomized cluster sampling. A simple conceptual model was explored and utilizing the goodness of fit indices in SEM, an optimal model was chosen. Then, utilizing 3-step hierarchical regressions and SEMs, the relationship between ADHD and MRB was assessed by modeling the possible mediators/moderators such as answering the cell phone and using the helmet. The results of hierarchical regression showed that answering the cell phone had both moderating and mediating effects on the relationship between ADHD (and the ASS subscale) with MRB. The final SEM, by introducing the mediating role of underlying variables, had a good fit on data (Normed Chi2 = < 5.0, RMSEA < 0.08, SRMR < 0.05, CFI and TLI > 0.90), wherein ADHD score (and the subscales) predicted the MRB score directly/indirectly (P < 0.05). A simple conceptual model was found to assess the mediating role of ADHD in motorcyclist risky behavior. Based upon the findings, training the techniques of and/or enforcement for controlling and improving riding behaviors and skills among ADHD motorcyclists, those who answer their cell phones while riding, un-experienced riders, and those who ride without wearing the helmet is strongly recommended.