The present study evaluated the effects of web‐based training on Spanish pre‐service and in‐service teacher knowledge and implicit beliefs on learning to write. A sample of pre‐service teachers and in‐service teachers from Mexico, Guatemala, Ecuador, Colombia, and Spain participated in the online course. Findings suggest that teachers may improve their knowledge of transcription skills (i.e., handwriting/typing, spelling), text production, and strategies for composing as necessary components of quality writing instruction. Effects were also found on the teachers' implicit beliefs. Finally, both pre‐service and in‐service teachers positively rated the online course received. Lay Description What is currently known about the subject Teaching children how to write demands a high degree of specialization. The benefits of web‐based training to professional development have been well‐documented in the literature. Preparing of pre‐service and in‐service teachers through an online context is limited in the field of writing. Teachers' knowledge, satisfaction, and beliefs have been commonly used as outcome measures to define high‐quality e‐learning instruction. What this paper adds A Spanish web‐based training was developed to improve professional development in writing instruction. The Trazo web‐based training changed teacher's beliefs about learning to write. Teachers learned more about the essential component of the writing process. Teachers' rating of the training and support website was highly positive. Implications for practitioners Web‐based training allows teachers to learn at their own pace. Teachers can improve their knowledge from virtually at any geographic location with an Internet connection. The Trazo web‐based training offers research‐based knowledge to Spanish‐speaking teachers.