Businesses in this century are facing a critical challenge concerning environmental problems. It has been argued that unstainable business operations are one of the major factors that contribute to the deterioration of the environment. Social pressures and current environmental regulations are now forcing business organisations to become more active in environmental management. Some organisations adopt environmental management practices for regulation requirements only, while many organisations go beyond those regulations by implementing voluntary actions to prevent environmental problems. Various studies have found that becoming involved in environmental management could lead an organisation to obtain a competitive advantage and to improve performance. However, becoming an environmentally friendly organisation does not mean overnight success, as it requires the organisation to have resources and capabilities that support environmental protection activities. According to the natural-resource-based view of the firm, a sustainable competitive advantage can be obtained when an organisation is able to utilise its unique resources and capabilities to support environmentally friendly economic activities. Moreover, it has been found that a pro-environmental attitude in the people in an organisation contributes to the successful implementation of those activities. This study builds upon the natural-resource-based view of the firm and the new environmental (ecological) paradigm to tackle the research question of what determinants are necessary to obtain a competitive advantage through proactive environmental strategies (PES). Therefore, the objective of this study is twofold: (1) to identify determinants that complement the adoption of PES, and (2) to detail the specific benefits that can arise from the adoption of such strategies. Previous studies have shown that the adoption of PES can be driven by four determinants: the organisational capabilities of learning, innovation, and quality management, and the pro-environmental attitude of management. However, these factors have been studied separately in different models. Moreover, previous research on PES has focused extensively on the manufacturing and service industries in developed economies. Little is known about the determinants and consequences of the adoption of PES in developing countries where inadequate environmental sustainability is a major threat to their economies. Therefore, this study focuses on a developing country, Thailand, which depends heavily on the tourism industry, but where environmental problems endanger the future of this industry. A holistic research framework is proposed to study the adoption of PES in this country. This study employed an explanatory mixed-methods approach, combining quantitative and qualitative methods, in order to enhance the generalisability of the findings. The quantitative data were collected through paper and online self-administered surveys. The structural equation modelling with partial least squares (PLS-SEM) was applied to analyse 97 questionnaire responses exploring the relationships between several variables in the research model. Eleven semi-structured interviews were subsequently conducted to find explanations to the quantitative findings. The results from quantitative and qualitative data reveal that pro-environmental attitudes of owners and top management, as well as learning orientation, innovativeness, and quality management capability are the necessary determinants for the adoption of PES in the hotel industry in Thailand. Although the quantitative analysis shows that pro-environmental attitudes of departmental managers have no direct effect on PES, the qualitative findings provide an explanation that the pro-environmental attitude and support of owners and top management are more important for the adoption of PES in hotels in Thailand which have a centralised organisational structure. In addition, this study extends the natural-resource-based view of the firm by arguing that businesses in both developed and developing economies can obtain competitive advantage from the adoption of PES supported by their unique organisational capabilities including learning orientation, innovativeness and quality management capability. Even though the passive learning style, the centralised organisational structure, the seniority issue in Thai culture, and the considerateness (in Thai called ‘Kreng Jai’) could potentially affect the learning climate in hotels, it is argued that learning capability is essential for hotels that aim to achieve sustained competitive advantage through PES. In addition, it was found that each capability complements the adoption of PES in a different aspect. Therefore, these capabilities are equally necessary in the adoption of PES. It can be concluded that all determinants found in developed economies are also important for the adoption of PES in developing economies. This study confirms that PES contributes to several organisational outcomes. More specifically, green strategies lead directly to positive environmental performance in terms of the consumption of utilities, waste management, and environmental risk management and to quality performance in terms of internal business processes, employee and customer satisfaction, leading to cost competitiveness and competitive advantage through differentiation. Moreover, both cost and differentiation competitiveness contribute to financial performance in terms of operating profit, return on environmental related investment, sales volume and operating cash flows. As this study focusses exclusively on a developing country, findings will extend previous studies by adding to the literature showing that PES is highly relevant for the hotel industry in both worlds. Positive organisational outcomes can be obtained from the adoption of PES for hotels in both developed and developing economies. The theoretical and managerial contributions of this thesis could pave the way for the successful implementation of green initiatives in Thailand which, in turn, could improve its travel and tourism competitiveness.