This paper examines company valuation in the Athens Stock Exchange (ATHEX) over the period 2005–2023, a period marked by substantial market expansion, sovereign-debt crisis, capital controls, and gradual recovery. Using primary ATHEX data, the study first documents the evolution of listed firms, listings and delistings, market capitalization, and the effects of major macro-financial shocks on the Greek equity market. It then reviews and applies a broad set of valuation approaches, including Discounted Cash Flow models, dividend discount models, relative valuation multiples, residual income, EVA/MVA, and asset-based methods. Complementing this framework, the empirical analysis investigates Enterprise Value (EV) for an unbalanced panel of 265 ATHEX-listed firms over 2003–2022, covering 3,364 firm-year observations, and relates EV to firm fundamentals and macroeconomic indicators such as the ASE General Index, sovereign bond yields, GDP, unemployment, and inflation. The evidence indicates that ln(EV) is dominated by persistent firm-specific heterogeneity, with between-firm effects accounting for 89.8% of total variance. Panel unit-root tests further suggest that EV is non-stationary in levels and behaves as a random walk without drift, while its relationship with the ASE General Index is statistically significant but weak and not supported by a robust long-run cointegrating relation. Finally, a comparison of fourteen valuation methods against observed EV across 3,299 firm-year decisions shows that method performance is not random. Asset-based approaches, especially the property-value method, become increasingly dominant during and after the 2009–2015 crisis, as income-based methods lose accuracy when profitability deteriorates. Overall, the findings indicate that valuation accuracy in the Greek market is context-dependent and should rely on firm-specific, sectoral, and macroeconomic conditions rather than on a single universal method.