Engineering degree programmes include a significant amount of practical work for which national accrediting bodies stipulate a set of laboratory-learning outcomes. This paper sets out to understand how students’ interactions in the laboratory contribute to the attainment of laboratory-learning outcomes. The investigation was conducted in the traditional face-to-face laboratory mode. Results from surveys of final-year students and instructors are reported. Students’ and instructors’ perspectives of the relative importance of four main types of student interaction to meet each of the Engineers Australia laboratory-learning outcomes are also presented. Students primarily expected to interact with instructors more than with students (directly or through observation of interactions) or equipment for their achievement of the learning outcomes, whereas instructors reported that all of the interactions are important to achieve the learning outcomes.