Genre analysis is today's dominant approach for textual analysis, especially in the ESP learning and teaching profession. Adopting this approach, the present study compares the Introduction chapters of MA theses in ELT (English Language Teaching) written by Thai students to those written by American university students based on the move-step analysis. Two sets of corpora comprise 30 TSI (Thai student Introduction) and 30 ASI (American student Introduction) Introduction chapters from the theses that followed the traditional five-chapter pattern or ILrMRD. All the TSI and ASI datasets were purposively collected from two electronic databases of graduate theses and dissertations, publicly known ThaiLis Digital Collection and ProQuest Dissertations and Theses. These were subsequently analyzed using genre analysis approach. The modified CARS model introduced by Bunton (2002) guides the move-step analysis. To ensure the coding reliability and consistency, the coding analysis of a subset of the entire datasets between the researcher and an expert coder was checked, and the coding agreement was at a highly satisfactory level. The findings demonstrated that both Thai and American MA students followed the moves and steps proposed in the framework to construct their Introduction chapters rhetorically. Both similarities and differences were discovered in the Introduction chapters investigated, in terms of the communicative purpose, the frequency of move-step occurrences, and the move-step classification. Pedagogical implications drawn from the present study are useful for EAP practitioners and research writing instructors, allowing ESL/EFL teachers to equip their graduate students with an appropriate rhetorical outline for thesis Introduction composition.