This thesis examines how and to what extent the intensity of corporate environmental management strategy implementation (i.e., the “corporate environmental management maturity”) affects environmental management accounting at the firm level. Notwithstanding the apparent connection between corporate environmental management strategy and environmental management accounting, the existing literature discusses these two fields only minimally. More specifically, the extant literature on the intensity of corporate environmental strategy is relatively sparse on the contribution and role of accounting (i.e., environmental management accounting). In contrast, environmental management accounting literature covers only a static body of practices neglecting the intensity of corporate environmental strategy implementation. Consequently, the literature on these two fields has established themselves in their own rights with limited dialog. This thesis thus has three sub-objectives: a) to identify how institutional pressures influence environmental management maturity in organizations, b) to investigate how environmental management maturity affects environmental management accounting implementation in organizations, and c) to examine how companies implement specific environmental management accounting practices in different stages of corporate environmental management maturity. In order to establish the link between these two fields while addressing the three subobjectives, this thesis follows a “thesis by publication” format, which consists of six interconnected empirical research papers presented in academic journal article format (Papers A to F). In its design, the thesis follows an explanatory sequential mixed-method approach, in which the data was collected in two phases covering both quantitative and qualitative data from companies in Sri Lanka. Paper A addresses the first sub-objective by highlighting how the various institutional influences exert pressure on corporate environmental management maturity. These pressures lead to a top-down process of diffusion and the simultaneous counter-process of invention by which the lower-level organizational actors shape and change their environmental management practices. More precisely, it shows that coercive pressures primarily develop corporate environmental management strategies at the reactive stage. In contrast, mimetic pressures exert the most considerable influence at the preventive stage. Combined mimetic and normative forces influence the environmental strategy at the proactive stage. This study further shows that although the organizations may face different institutional influences, their internal responses can also be formed by the organization’s specific circumstances. It highlights the need to look beyond social system-based theories for a greater in-depth understanding of the corporate environmental activities, including environmental management accounting at the firm level. In respect of the second sub-objective, i.e., to investigate how environmental management maturity affects environmental management accounting implementation in organizations, three papers were designed based on the contingency theory (Papers B to D). All three papers found evidential support to indicate that environmental management accounting implementation is significantly different at each of the three environmental management maturity levels. More broadly, the thesis identified this difference of environmental management accounting implementation from three aspects: a) application of domain-based environmental management accounting tools (i.e., specific and integrative tools), b) use of environmental management accounting for functional purposes (i.e., for decision making and control and stewardship uses), and c) information characteristics of environmental management accounting (i.e., scope, timeliness, aggregation, and integration). Despite the negligible variations, the results generally indicate that environmental management accounting evolves to innovate and diversify in line with the intensity of the corporate environmental strategy for dealing with the more sophisticated environmental management activities in support of broader corporate environmental objectives. This thesis thus provides evidence that the organizational context, i.e., environmental management maturity, plays a significant role in how and to what extent corporate entities adopt and implement environmental management accounting practices. In order to achieve the third sub-objective, i.e., to examine how companies implement environmental management accounting practices in different stages of corporate environmental management maturity, two studies were designed (Papers E and F). Accordingly, they analyzed energy accounting (Paper E) as a specific tool and eco-control in sustainable agriculture management (Paper F) as an integrative tool. Similar to the other findings of the thesis, these papers, too, highlighted the impact of the environmental management maturity stage of an organization on the application of specific and integrated environmental management accounting tools. More precisely, Paper E provides evidence of a high level of use of energy efficiency strategies across all the levels of environmental management maturity despite the varying degree of use of energy accounting for sufficiency and consistency strategies. Paper F further submits that the adoption of integrative environmental management accounting tools such as eco-control requires organization-wide changes ranging from policy formulation and information management to decision support implementation and communication. In sum, these two papers highlight the importance of the management of environmental accounting information in corporate environmental sustainability in some areas that were traditionally regarded as technical such as energy management and sustainable agriculture management. Overall, the papers developed for this thesis, which followed both quantitative and qualitative approaches, provide evidential and theoretical support that the intensity at which the corporate environmental strategy is adopted has a crucial bearing on the implementation of environmental management accounting at the firm level in various aspects.