The use of a product that is not environmentally friendly has become a crucial issue in preserving the environment. The waste from marketing activities, such as plastic waste, is currently becoming a threat to the environment and the economic sector. Companies must understand this problem and respond to it by providing products or services that can minimize environmental damage. The purpose of this study is to examine the influence of green knowledge, green brand, and willingness to be environmentally friendly toward a green purchase behavior. The object of this study is consumers in Bandung City, Indonesia, who have the experience of purchasing environmentally-friendly products such as eco-bag (shopping bags) as a means to minimize plastic waste. This study uses a quantitative method with explanatory research. The samples are taken from 125 respondents who were collected in three days in different places. The results of this study indicate that there is a quite high influence of green knowledge, green brand, and willingness to be environmentally friendly in explaining consumer purchasing behavior. This study provides the implication that in order to increase the purchase of green products, companies need to educate consumers regarding the benefits of using an environmentally-friendly product and provide a brand image that can support and promote green marketing.