Little is known about students' engagement in school writing tasks and the methods that should be used by the researchers to assess this engagement. This exploratory study examines the relationship between the engagement reported by elementary school students (N = 136) in a handwriting and keyboarding activity (Likert scale questionnaire) and their actual behaviors in such situations. An observational checklist was created to capture engagement behaviors in these writing contexts. Correlational analyses showed that, overall, self-reported engagement scores were positively correlated with the frequency of the behaviors observed in both contexts. The discussion focuses on the relevance of observational checklists and questionnaires for capturing students' engagement in writing tasks, and opens to the conceptual links between engagement and motivation.