The main purpose of the present study was to develop and evaluate a WebQuest instruction on Nutrition using WebQuest template, known as NutriQuest. NutriQuest was developed to improve Form 2 students' understanding of fundamental nutrition concepts and its application in daily life, to improve critical and creative thinking skills and to enhance cooperative learning in a web-based learning environment. The specific goals of the evaluation of NutriQuest with students and science teachers were focused on: (i) suitability of content and design of the NutriQuest website, (ii) attitudes toward WebQuest instruction, and (iii) identifying the factors affecting the usage of WebQuest instruction. The qualitative-naturalistic-formative approach was adopted in this study where the focus was on programme improvement, and exploring a variety of effects on participants. Three main techniques were used to collect data; namely observations, interviews, and analysing documents. The documents used in this study were students' diaries and their learning artefacts such as worksheets and presentation materials. Based on the findings, three conclusions could be drawn from the study. They were: (i) the NutriQuest website facilitates science learning on nutrition for Form Two students, (ii) teachers and students showed positive attitudes toward WebQuest instruction in science, and (iii) the usage of WebQuest instruction was affected by several factors. (Contains 1 table and 1 figure.)