This study aims to identify patterns of the system of theme in Spanish in 28 educational linguistics' articles, an emerging field in Latin America. Results show a high number of textual and elaborated interpersonal Themes (especially in Conclusions), alongside a frequent choice of marked Themes (especially in Introductions) which adjust thematic strings, while the Subject is usually explicit and previous to the verb. Educationally-oriented articles tend to use more interpersonal Themes and preposed explicit Subjects, in what seems to be a disciplinary validation struggle. This research can help understand the construction of a new disciplinary discourse, connecting semantic and lexicogrammatical patterns to epistemological frameworks, while providing evidence to the realization of Theme and Subject across stages, disciplines and languages.