Energy use in British homes is a significant contributor to national greenhouse gas emissions, and the improvement of energy efficiency in residential buildings has long been an important topic in policy discussions. The lack of investment in energy-saving measures is particularly challenging in the private rented sector, and there are significant research and data gaps in understanding the retrofit behaviour of private landlords. In this study, we present the results of a detailed survey on retrofit behaviour of 1069 British private landlords. The survey assesses the engagement of landlords with 18 different energy efficiency measures, as well as their attitudes, perceptions, norms and a number of other characteristics. We use the data collected in the survey to produce 7 behavioural “typologies” of landlord retrofitters, by clustering respondents based on their socio-demographic and business characteristics. In addition to providing descriptive evidence of landlords' retrofit behaviour, our results reveal a number of opportunities for segmenting the landlord population into target groups for future policy interventions. By tailoring retrofit incentives to the needs and motivations of these groups, policy-makers can effectively engage landlords with specific energy-saving technologies, increasing the likelihood of retrofit uptake and accelerating the transition to an energy-efficient private rented sector.