Learning to write is challenging for young children, as they must integrate their still-developing fine motor skills with an understanding of written language to produce a mark that has meaning. Complicating things more is the fact that children are often asked to produce a variety of written products with varying task demands (e.g., writing single letters vs. combining these letters to form entire words or sentences). Although theoretical models of writing highlight the importance of both self-regulation and fine motor skills for writing, our current understanding of how these two constructs interact to support writing remains incomplete. Thus, the current study examined the extent to which self-regulation moderates the relation between fine motor skills and early writing development – and whether this relation differs by writing task difficulty. To address this, two diverse cross-sectional samples of 3-5-year-old children from Head Start programs were assessed on fine motor skills, self-regulation, and a variety of writing tasks at the beginning (N = 333) and end (N = 405) of the preschool year. Hierarchical regression analyses were conducted to examine the potential moderating association between fine motor skill and self-regulation on early writing skills, with separate models fit for each writing task. After controlling for demographic factors, results indicated that self-regulation was important at the beginning of the year for children with higher levels of fine motor skills when completing a challenging writing task. Self-regulation was also important at the end of the school year for both 1) children with lower fine motor skills but only for the simpler writing tasks and 2) for children with higher fine motor skills on the more challenging writing tasks. Findings suggest that the relation between self-regulation and writing is dependent upon task difficulty and that self-regulation and fine motor skills may compensate for deficits in one or the other skill when children perform writing tasks. (author abstract)