With today?s increasing environmental threats, many people have started to pay attention to sustainable development to protect the environment and society. This study determined the effect of green brand positioning, attitude towards the green brand, and environmental concerns on green product purchase intention. In addition, this study evaluated green brand knowledge as a moderator on the association of green brand positioning, attitude towards the green brand, environmental concern, and green product purchase intention. The respondents were selected using the inquiry portal of ABC Group of Companies, a real estate developer in the Philippines. Based on the list, the age of the customers was filtered to meet the criteria of age 26-41, which is considered millennial and a potential buyer specifically in Cavite and Batangas province. The researcher employed a causal research design, purposive sampling, and a quantitative research methodology to quantify the research variables and determine the relationship between the independent variables. The research found that green brand positioning, attitude towards the green brand, and environmental concern positively and significantly affect green product purchase intention. At the same time, the study found that green brand knowledge does not significantly moderate the association of green brand positioning, attitudes towards green brand knowledge, environmental concern, and green product purchase intentions.