This paper presents a systematic review on behavioural science interventions in the human development and environmental/climate fields in developing countries. The review synthesizes evidence on five specific behavioural interventions – feedback, reminders, salience (communication), salience (experience design), and goal setting – and how these influence development and environmental/climate outcomes. It aims to facilitate the use of evidence in informing policy and practice decisions within the environmental/climate and development fields, particularly in the GCF and IFAD.