The study of the Research Article (RA) genre has been dominated by genre analysis and corpus linguistics focusing on rhetorical moves and, or lexicogrammar, with little attention to the level of the message and the realization of different types of Theme and progression patterns. To the best of our knowledge, there is a lack of comparative studies investigating similarities/differences in the use of theme in electrical engineering RA Introductions written by native English-speaking (NES) scholars and non-native English-speaking (NNES) Saudi scholars. We address this gap using Systemic Functional Linguistics (SFL) approach to analyze the texture of electrical engineering RA Introduction sections written by NES scholars and NNES Saudi scholars from a message perspective. The research questions aimed to quantitatively and qualitatively investigate (1) Theme types, (2) thematic markedness, and (3) thematic progression patterns in the two data sets. After reviewing comparative research on message structure, we analyzed 117 RA Introductions written by experienced NES/NNES authors. The results accord with research comparing thematic organization in native English scholars' writings and those from cultural background other than Arabic. The findings showed that NESs' and Saudi NNESs' introductions overlap at a clause level, but they start to diverge beyond the clause. This study provides a good starting point for understanding NNES Saudi scholars' use of underexplored linguistic items. The results of the current study offer insights for academic writing instruction and material developers.