Not‐for‐profit (NFP) organisations experience a tension between societal perceptions about maximising mission expenditure on one hand, and their need to accumulate reserves to ensure longer term financial sustainability on the other. While studies have examined the level of reserves in UK and US contexts, there is little Australian research or guidance about what constitutes an appropriate level of NFP reserves. This paper examines the levels and implications of the reserves of 52 Australian NFP non‐governmental organisations (NGOs) over eight years, identifying two groups. Spenders, with less than three months of expenditure in reserve, were more financially vulnerable, had higher levels of debt, yet spent a relatively greater proportion of their revenue on mission‐related activities than savers. Savers, with more than three months’ reserves, demonstrated a greater proportion of revenue from fundraising, proportionately greater equity levels, and higher returns on assets. Providing unique insights into the financial reserves of Australian NGOs, this empirical study contributes to existing NFP literature on reserves, which to date has focused primarily on US and UK contexts. Further, we propose that by developing, monitoring and communicating their reserves’ strategies, NFP boards and managers will be able to improve their organisations’ financial sustainability and manage societal perceptions about reserves.