Purpose: Small scale enterprises are vital to economic growth, employment creation, and poverty reduction in Nigeria, yet their sustainability is increasingly threatened by economic crimes, especially within the informal sector. This study was conducted to examine the impact of economic crimes on the sustainability of small scale enterprises in Nigeria, identify the major forms of crimes affecting them, assess their effects on business performance, growth, and survival, and analyse how these crimes influence decisions on formalisation and long-term viability. Design/methodology/approach: The study is grounded in the Fraud Triangle Theory and Routine Activity Theory and adopts a systematic review design. It relies on secondary data drawn from peer-reviewed journal articles and institutional reports published between 2019 and 2024, which were analysed through qualitative synthesis. Findings: The findings reveal that bribery, extortion, fraud, and cybercrime are the most prevalent economic crimes confronting small scale enterprises in Nigeria. These crimes contribute to financial losses, rising operational costs, reduced profitability, and weakened growth prospects. They also discourage many enterprises from formalising their operations. Weak regulatory oversight and the normalisation of corruption further increase business vulnerability. Limitations and research implications: The reliance on secondary data limits empirical depth. Future studies should employ primary data and sector-specific investigations to provide stronger evidence. Practical implications: Policymakers can apply the findings by strengthening institutional frameworks, improving regulatory enforcement, adopting digital monitoring systems, and simplifying business registration processes. Originality/value: The study adds value by linking economic crime directly to enterprise sustainability and formalisation within Nigeria’s informal sector.