Purpose- Environmental concern is a key issue for today's society, and consumer behavior is one of the reflection areas of environmental concern in today's marketing. Understanding the behavior patterns of consumers acting with the awareness of protecting the environment, evaluating their practices, and examining their opinions will be beneficial for marketing research. This paper aims to explore an online community discussing the Zero Waste concept and evaluate the themes in the discussion content. With an exploratory aim, this study examines the posts on an online community on a social media platform (Reddit/ZeroWaste) to evaluate community discussion for the Zero Waste concept. Methodology- Data collected from Reddit community of ZeroWaste with the filter of “top posts” and “all time” is used for the sample of the study. Consistent with the exploratory purpose of the study, thematic analysis methodology is employed on community posts. Content is evaluated in two dimensions -post type and content categories- and four post types and thirteen content categories are concluded in the study. Findings- Post types include information, instruction, personal experience, and discussion with community. Content categories include zero waste cases, showcase of zerowaste lifestyle and applications, upcycling, repurposing, reusable items/reusing, recycling, food waste, do it yourself, news sharing, product instruction, discussion about responsibility, environmental awareness, and memes/humor. Conclusion- Post types can signal how the discussion is shaped in the community, while content categories are reflecting the different type of themes in the content. "Zero Waste cases" theme expresses the industrial applications, therefore companies can use this theme to benchmark themselves and understand the applications. "Showcase of Zerowaste Lifestyle and Applications" theme can signal the consumers’ behaviors about the topic. Other themes such as "Upcycling, Repurposing, Reusable items / Reusing, Recycling" also shows the different types of zero waste applications. Evaluation of the post types and content categories included in the conversation of Zero Waste community can help managerial decision-making process about sustainable marketing practises and consumer behavior.