<![CDATA[Purpose: This study examined whether an integrated STEM–Internet of Things (IoT)–Education for Sustainable Development (ESD) professional-development program was associated with differences in junior secondary science teachers’ competencies at the group level. Methods: A quantitative, pre-experimental repeated cross-sectional pretest–posttest design analyzed 29 valid pretest and 33 valid posttest responses from the MGMP IPA teacher community in Sumedang, Indonesia. A researcher-developed assessment comprised 10 multiple-choice items and five constructed-response items (maximum total score = 100). Descriptive statistics, normalized gain based on group means, Welch’s independent-samples t-test, Mann–Whitney U, and Hedges’ g were reported. Findings: The mean total score was higher at posttest (83.24, SD = 11.07) than at pretest (59.34, SD = 16.22); the descriptive normalized gain was 0.588. Welch’s t(48.49) = 6.682 (p < .001), and Hedges’ g = 1.72 indicated a large group-level separation. The largest multiple-choice differences concerned the Blynk platform and ESP8266/Wi-Fi modules, whereas constructed responses showed higher scores for sensor-data interpretation and IoT–ESD project design. Implications: Integrated technical practice, data interpretation, and pedagogical design may provide a useful structure for science-teacher professional development. These cross-sectional comparisons cannot establish within-teacher growth, program causality, or transfer to classroom practice. Originality: The study examines factual, interpretive, and design-oriented competencies within a combined STEM–IoT–ESD teacher-learning program.]]>
