The process of learning how to write is a demanding, slow, and complex process. Primary school students often experience problems in writing and, therefore, teachers should provide scientifically validated strategies to empower their performance, such as Self-Regulated Strategy Development (SRSD). Reflecting on the changes in the social reality and students’ personal interests, the inclusion of Information and Communication Technologies (ICT) in the educational context and practice in writing has also become exceedingly relevant. However, using ICT associated to other teaching methodologies is not always explored in the classroom. In a quasi-experimental study, 178 fourth grade students participated in an opinion essay writing intervention, during 12 weeks (90 min/week), using SRSD instruction model (n = 89) and an ICT variant of SRSD called SRSD + ICT model (n = 89). We analyzed the impact of these two interventions through the analysis of opinion texts produced, by handwriting, for students one week before and one week after the intervention according to the elements, quality, number of words and number of linking words. Both showed positive results in the students’ writing skills, although the results from the SRSD + ICT model were better. These results reinforce the pertinence and usefulness of this model in the teaching-learning process of writing that should be discussed and tested in different contexts.