This research and development study aimed to design an interactive e-module based on Flipping Book Publisher to improve expository writing skills and learning motivation among fifth-grade elementary school students. A preliminary needs analysis conducted at an elementary school in Makassar City revealed that most Grade V students struggled with expository writing and perceived conventional, teacher-centered instruction as unmotivating, indicating both a skills deficit and an unaddressed motivational gap. The study employed the Four-D model (Define, Design, Develop, Disseminate) with a one-group pretest-posttest design, without a control group, to design, validate, and preliminarily evaluate the e-module. The module integrates six multimedia components grounded in the Cognitive Theory of Multimedia Learning, constructivism, and self-determination theory. Data were collected from three expert validators, 38 Grade V students, and 15 teachers using validation sheets, student and teacher response questionnaires, a writing skills test, and a motivation questionnaire. Data were analyzed using percentage scoring, normalized N-gain, and exploratory structural equation modeling (SEM) with AMOS 24.0. Results indicated that the e-module was categorized as very valid (87.5%) and very practical (90.5%). Writing skills improved with a moderate mean N-gain of 0.56 across five writing aspects, and 86.9% of students achieved high or very high motivation after the intervention. Exploratory SEM showed positive associations between e-module use and both writing skills (β = 0.72) and motivation (β = 0.68), as well as between writing skill gains and subsequent motivation (β = 0.41). Given the single-group design and limited sample size relative to model complexity, these path estimates remain preliminary and should not be interpreted as causal evidence. Overall, the e-module shows promising early evidence of validity, practicality, and effectiveness, warranting further studies with larger samples and comparison groups before broader adoption.