This article describes the development of the Writing Readiness Inventory Tool in Context (WRITIC), a measurement evaluating writing readiness in Dutch kindergarten children (5 and 6 years old). Content validity was established through 10 expert evaluations in three rounds. Construct validity was established with 251 children following regular education. To identify scale constructs, factor analysis was performed. Discriminative validity was established by examining contrast groups with good (n = 142) and poor (n = 109) performers in paper-and-pencil tasks. Content validity was high with 94.4% agreement among the experts. Two reliable factors were found in the performance of paper-and-pencil tasks with Cronbach's alphas of 0.82 and 0.69 respectively. The contrast groups differed significantly in two WRITIC subdomains: "Sustained attention" and "Task performance". Our findings indicated that the WRITIC is feasible for use in the classroom.