Green building design and assessment have drawn significant attention from researchers over the past few decades. Despite the advancements in this research area, multiple stakeholders' perspectives, as a social and non-technical research area, has been vastly underestimated in green buildings and sustainable development literature. This research aims to (1) examine the knowledge, attitude and practice (KAP) of multiple stakeholders (e.g., architects, engineers, sustainability consultants, developers, contractors and suppliers) towards green building design and assessment process in the New Zealand Architecture, Engineering and Construction (AEC) industry, (2) explore motivations and barriers to green buildings on the national level and (3) identify and contrast each stakeholder group's motivations and barriers to adopting green building design standards and certifications. Data were collected from 215 multiple stakeholders in New Zealand using a KAP questionnaire survey. Statistical analysis using Kruskal-Wallis H test and Correlation tests (Pearson, Kendall and Spearman) were conducted to explore the relationships and differences in the KAP levels of the stakeholders. The results indicate adequate knowledge and positive attitude of the multiple stakeholders towards green building design and certifications. However, practices of green building design and assessment are still limited in New Zealand. The stakeholders' knowledge level is significantly and positively correlated with their attitude and practice. The results, moreover, reveal an attitude-practice gap among the multiple stakeholders which needs to be bridged. Practical implications are proposed to enhance the KAP levels of the multiple stakeholders and facilitate the adoption of green building design standards and certifications in New Zealand.