Thesis (Ph. D. Commerce (Business Management)) -- University of Limpopo, 2021 / The current work assessed the link between environmental sustainability commitment and financial performance of firms listed on the Johannesburg Stock Exchange (JSE). Broadly, the researcher aimed to establish whether environmental sustainability commitment as measured by energy efficiency, water efficiency, waste management, carbon emission reduction, material efficiency, green products and services innovation, environmental compliance and stakeholder engagement do affect financial performance. Furthermore, the study tested the moderation effect of industry type on the link between environmental sustainability commitment and financial performance. The study was quantitative in nature with a case study research design. The longitudinal design was adopted where the researcher collected panel data from 2011-2018. The population of the study included all firms listed on the JSE Responsible Investment Index in South Africa. The sample constituted of 32 firms listed on the FTSE/JSE Responsible Investment Index in South Africa. The researcher employed panel regression analysis model to analyse the data. Specifically, the Feasible Generalised Least Squares regression model was utilised in this study. Financial performance was treated as the dependant variable and was measured using return on equity (ROE), return on assets (ROA), earnings per share (EPS), share price and Tobin’s q. The independent variables of the study included components of environmental sustainability; energy efficiency, water efficiency, waste management, carbon emission reduction, material efficiency, green products and services innovation, environmental compliance and stakeholder engagement. Control variables such as firm size and liquidity were used in the study. Mixed findings emerged from the statistical tests. The findings on the relationship between energy efficiency and financial performance suggested that energy efficiency has no significant effect on financial performance as measured by ROE, ROA and Tobin’s Q. Conversely, a significant and negative link was established when energy efficiency was tested against EPS and share price. A significant positive relationship was established between water efficiency and EPS as well as share price. The results further revealed that being water efficient may not significantly affect financial performance when ROE, ROA and Tobin’s Q are used. The results showed no significant relationship between waste management and all dependent variables. The findings indicated that carbon emission reduction was positively and significantly related to EPS and share price. Nevertheless, it was discovered that the nexus between carbon emission reduction and measures of financial performance such as ROE, ROA and Tobin’s Q was positive but insignificant. In terms of material efficiency and financial performance, the findings indicated that material efficiency had an insignificant effect on ROE, ROA, share price and Tobin’s Q. Nevertheless, a significant and negative relationship was established between material efficiency and EPS. Considering green products and services innovation and performance, the findings established a significant negative relationship between green products and services innovation and share price. However, the results further indicated that the link between green products and services innovation and ROE, ROA, EPS as well as Tobin’s Q was insiginificant. The findings exhibited that environmental compliance was negatively related to ROE and Tobin’s Q yet positively related to EPS and share price. An insignificant relationship was established between environmental compliance and ROA. Stakeholder engagement was found to be positively related to EPS. It was also found that the effect of environmental sustainability commitment on financial performance did not differ based on the industry type. The findings rather showed that firms within each industry had specific environmental sustainability commitment and financial performance combinations which were unique to that industry. It was also found that industry type significantly moderates the relationship between environmental sustainability commitment and financial performance. It was concluded that firms can enhance their financial performance from environmental investments which are unique to certain industries as determined by key stakeholders in that sector. Recommendations were made to different stakeholders such as the government, corporate managers and organisations which provide environmental reporting guidelines to play an active role in promoting environmental sustainability commitment among firms. Keywords: environmental sustainability commitment; financial performance; firms; sustainable development; Johannesburg Stock Exchange; South Africa