Retail internationalization offers immense growth opportunity, yet many global brands fail to sustain operations after entering foreign markets. Examples such as Walmart in Germany, Marks & Spencer in France, Carrefour in Singapore, and Shoprite in Nigeria highlight that international expansions can collapse despite strong brand recognition. This study analyzes root causes of international retail failures using case analysis across 14 multinational brands, expert interviews, and cross-market comparative frameworks. Findings show that failure is driven by misaligned localization strategy, regulatory friction, weak supply chain integration, cultural mismatch, and currency volatility. A diagnostic root-cause model is proposed to guide future global retail strategies.