Architecture, Engineering and Construction (AEC) industry significantly contributes to environmental degradation through material and energy flows and a huge amount of waste generation as a result of the demolition and refurbishment of buildings. Evidence from environmental psychology literature suggests that being informed about environmental problems does not automatically translate to pro-environmental behaviour (PEB). Clarifying the profiles and perspectives of designers who tend to display low- and high-PEB can provide insights for developing environmental intervention strategies. A questionnaire was designed and delivered to the members of Istanbul Chamber of Architects (CAT). Hierarchical cluster analysis was conducted to classify respondents as relatively low-PEB and relatively high-PEB designers, where PEB was operationalized by the self-reported adoption and implementation of LEED criteria in projects within the past 10 years. Following the classification of design professionals according to PEB scores, quantitative data from 274 respondents and qualitative data from 95 respondents were analysed respectively. Keeping other factors constant, findings suggest that the predictive power of awareness about pro-environmental practices in the business domain appears stronger when compared with that of general awareness of people about environmental problems. Apart from contributing to a theoretical understanding of PEB at the workplace, findings provide insights into developing target-group-specific intervention strategies, as they indicate that being technically informed may more easily translate to PEB in the business setting if appropriate motivational incentives are used and continuing professional development programs are designed, especially for the low-PEB designers.