<p>This study undertook a needs analysis to inform the development of a blended laboratory module for teaching osmosis in secondary school Biology. Guided by the ADDIE instructional design framework, the study examined students’ conceptual understanding, laboratory experiences, exposure to virtual laboratory learning, and perceptions toward blended learning. A descriptive survey design involving 51 Form Four Biology students from five Malaysian secondary schools was employed. Data were collected using questionnaires comprising closed-ended and open-ended items, while 32 students voluntarily participated in an osmosis achievement test. The results indicated a discrepancy between students’ perceived understanding and actual achievement. Although most students reported understanding osmosis, only 9.5% of students who participated in the achievement test achieved high scores (11–15 marks), indicating limited conceptual mastery. The study also identified inconsistencies in laboratory practices, with 37% of students reporting experiments conducted without structured module guidance. Furthermore, only 37% had experience with virtual laboratory activities, while most students reported limited teacher use of virtual laboratory applications. Despite these limitations, students consistently expressed preferences for multimedia-rich, interactive, and inquiry-based learning approaches. The findings highlight the need for a blended laboratory module integrating physical and virtual experiments to enhance conceptual understanding, experimental skills, manipulative skills, and self-efficacy. The study provides empirical guidance for the subsequent design and development phases of the module within the ADDIE framework. The study contributes to Biology education by providing an evidence-based foundation for designing blended laboratory instruction that aligns with students’ learning needs, laboratory experiences, and digital readiness.</p>