Abstract: Sri Lanka Navy (SLN) spends a considerable amount of capital on monthly electricity bill payments, which, if saved, could be expended for the benefit of the Navy. The present human strength of the Navy is approximately 55,000, and this figure directly influences the electricity consumption in the Navy. Owing to the fact that, the human behaviour can play a vital role in conserving energy, this study is focused on investigating and analysing the challenges influencing energy conservation through a behavioural approach of SLN personnel. The study followed a qualitative approach and necessary data was obtained from the officers and sailors serving at Sri Lanka Navy Ship (SLNS) Rangalla through an open-ended questionnaire and also through structured interviews. The study revealed that, awareness, supervision, restriction, coercion, referent power, attitudes, responsibility, feedback, and motivation are the factors affecting human behavioural approach.