Purpose: The purpose of this paper is to evaluate the usability and interface design of e-learning portal developed for primary schools in Singapore. Design/methodology/approach: Using Singapore-based learning EDvantage (LEAD) portal as a case study, this paper reviews and analyses the usability and usefulness of embedded learning objects (LOs) for students aged nine years and above through learning theories such as behaviourism, cognitivism and constructivism and interface design theories by Shneiderman, LO review instrument and laws of gestalt psychology. Findings: Analysis found the portal to be sufficiently motivating and appealing to learners at Piaget's concrete operations stage. The interface design is universally structured and functional. An area for improvement highlighted in this case study is the lack of explicit mention of learning outcomes in the portal. Practical implications: Usability principles used in this case study should be provided by the Ministry of Education in Singapore to schools to ensure more standardized and rigorous selection process of e-learning portals. Originality/value: This evaluation provides schools with insights into the use of learning theories and usability principles for evaluation of learning objects designed for primary-going students. It aims to inform decision makers of issues in interactive design to consider before subscribing to any e-learning portals. It also provides a gauge of current usability level of commercially developed portals as usage of such portals continue to proliferate in the Singapore education system.