This study investigates about the relationship between institutional pressure and environmental management accounting (EMA) adoption level by applying new institutional sociology perspective to assess the pressures for EMA adoption level with reference to 38 listed manufacturing companies in Colombo Stock Exchange (CSE) in Sri Lanka, based on convenient sampling method. Data were collected through structured questionnaire distributing via e-mail and postal mail for accountant or financial managers as respondents. Reliability analysis, descriptive analysis and inferential analysis were applied to analyze the data and three hypotheses were tested by multiple regression analysis. Those hypotheses were constructed to reveal about coercive isomorphism, normative pressure and mimetic processes are positively influence for EMA adoption level. The results indicate the influences of education or/and training, and political or/and legitimacy are positively pressure for the adoption of EMA; although, the pressures on standard responses to uncertainty is insignificant for EMA adoption. In addition, Coercive isomorphism; responses to political influence or/ and legitimacy influences play vital role in pressuring on EMA adoption. Further findings supports to the practical implications of Accountant role and political/ legitimacy influences are important in managing environmental issues in an organization. This study has made preliminary understanding for the new institutional sociology perspective concerning the type of pressure that influences and, provides useful contribution to the present knowledge by exploring more explanations for environmental management accounting adoption in an unexplored context in Sri Lanka.