The mass production of baby formula by the dairy industry can harm the environment through plastic waste, carbon emissions, and land degradation. Many babies in the world, especially in Asia, depend on formula milk as their primary food source, contributing to milk production. This reliance persists due to a lack of awareness among mothers about the environmental drawbacks of formula milk, leading to a decline in breastfeeding. Therefore, taking urgent action to protect the environment and promote breastfeeding in all countries is critical. In this context, the Breastfeeding Mother Community which is a community on Facebook that can be used as a means for sharing education, has a key role in raising awareness of mothers. However, in the Breastfeeding Mother Community on Facebook content, there is no education regarding the negative impact of formula milk on the environment. Thus, this research aims to aims to find out how much knowledge the members of the Breastfeeding Mother Community on Facebook have regarding the negative impact of formula milk production on the environment and how this knowledge influences perceptions of behavioral control. This research uses the Theory of Planned Behavior (TPB), the current research approach, based on the Theory of Planned Behavior (TPB), seeks to verify the existence of a relationship between knowledge between environmental knowledge and perceived behavioral control and this research uses quantitative methods with data collected through distributing questionnaires. The objects studied in this research were the members of the Breastfeeding Mother Community on Facebook with a total population of 165,000 and a total sample of 400 respondents. The data analysis techniques used are descriptive analysis, normality test, simple linear regression analysis, hypothesis testing, and coefficient of determination test. The results obtained from the research are the influence of knowledge of the members of the Breastfeeding Mother Community on Facebook on awareness of perceived behavioral control showing that the variable Knowledge on the negative impact of formula milk production on the environment (X) has an influence on perceived behavioral control (Y) with a percentage of 28,2%. Meanwhile, the remaining is influenced by other variables that are outside of this research. Based on the analysis results, it has no significant influence, this can be seen from the calculated T value > T table (-4,742 < 1.965) which means that H1 is rejected and H0 is accepted.