<p>The aim of this study is to formulate and empirically test a theoretically grounded convergence equation for financial development. Building on the Solow framework, we derive a testable convergence equation for financial development and estimate it using the System GMM methodology. We examine a panel dataset covering 160 countries, both at the global level and within three income groups, spanning the years 1990 to 2024. Key findings can be outlined as follows: (i) there is robust evidence of unconditional convergence in financial development across the global sample and within all three income groups; (ii) when major macroeconomic controls are introduced, the analysis also confirms the existence of conditional convergence; (iii) the influence of macroeconomic variables on financial development convergence differs across income categories; (iv) trade openness is a significant driver in high-income and upper-middle-income economies, whereas inflation plays a central role in lower-middle and upper-middle-income economies; (v) institutional quality has a statistically significant impact on financial development convergence, but only within upper-middle-income countries. Overall, the study provides robust evidence of financial development convergence and highlights the key macroeconomic and institutional factors shaping the convergence process across income groups.</p>