This study examined the contribution of sensory regulation, child negative affect, and parenting behaviors to the development of effortful control in preschoolers. Another aim was to examine if parenting behaviors moderated the relationship between sensory regulation or between negative affect, and effortful control. Participants included a community sample of 577 4-year-olds and their parents. Negative affect and effortful control were measured by the negative affect and effortful control subscales of the Children's Behavior Questionnaire (CBQ; Rothbart, 2002). Sensory regulation was assessed by the Short Sensory Profile (Dunn, 1998). Parenting behaviors were assessed from a Videotaped Parent-Child Interaction Paradigm (NICHD Early Child Care Research Network, 1999). Results indicate that sensory regulation, negative affect, positive parenting and negative parenting were significantly related to effortful control. Contrary to expectation, parenting behaviors did not moderate the relationship between negative affect and effortful control and sensory regulation and effortful control. Positive parenting behaviors partially mediated the relationship between negative affect and effortful control and sensory regulation and effortful control. Implications of the findings and suggestions for future research are discussed.