Even though firm sustainability is a long-standing concern, just a few studies on micro, small and medium enterprises (MSMEs) sustainability have been conducted. Many studies have concentrated on a few particular sustainability criteria, but there is no comprehensive study on the subject from which to make concrete conclusions. The present research was inspired by the idea to examine how resources such as financial literacy, financial access and company development influence the sustainability of MSMEs. Data was gathered from 438 owner-managers of micro, small and medium enterprises through a questionnaire. The research discovered that financial literacy, financial availability and company growth are positively correlated with firm sustainability when using partial least squares. Surprisingly, the research found that financial access and firm growth moderate the anticipated connection between financial literacy and sustainability. As a result, policymakers and practitioners should ensure that firms have better access to financial resources, that owner-managers have the necessary financial literacy and that micro, small and medium-sized businesses grow effectively better firm sustainability.