This study systematically reviews the relationship between financial behavior and business performance in micro, small, and medium-sized enterprises (MSMEs). It aims to clarify how finance-related constructs are used in MSME performance research and to integrate fragmented evidence into a clearer financial behavior framework. The review followed the PRISMA 2020 framework. Articles were retrieved from the Scopus database on 5 April 2026 using TITLE-ABS-KEY searches combining terms related to financial behavior, MSMEs, and business performance. The search identified 878 records. After screening, 96 articles met the eligibility criteria, 30 were retained as priority studies for descriptive synthesis, and 15 core articles were selected for focused conceptual analysis. The narrowing process used explicit appraisal criteria covering conceptual relevance, performance linkage, and methodological or reporting adequacy. The review shows that financial literacy is the dominant construct used to represent financial behavior in MSME studies. However, the evidence also includes financial attitude, financial management practices, financial inclusion, digital finance, risk attitude, and financial capability. The 15 core studies indicate a generally positive pattern between financial behavior and MSME performance, either directly or through mechanisms such as access to finance, financial inclusion, innovation capability, enterprise risk management, financial well-being, and digital financial capability. The findings should be interpreted as narrative and indicative rather than causal or effect-size based. The review used Scopus as the sole database and relied on a focused synthesis of 15 core studies. Future research should use multi-database designs, longitudinal models, clearer construct separation, and empirical tests that distinguish digital financial capability from general financial literacy. This review does not claim that financial literacy is unexplored. Its contribution lies in clarifying financial behavior as a managerial capability that connects financial knowledge, financial practices, financial decision-making, and digitally embedded financial capability in MSME performance research.