The research aims to critically evaluate the readiness of Nigerian firms for internationalization within the context of the African Continental Free Trade Agreement (AfCFTA). It employs quantitative research methods and a survey of 118 businesses across Nigeria with various exportable products and geographical locations. The data, analyzed using SPSS statistics, showed high reliability with a Cronbach’s alpha index of 0.939. Approximately 89% of respondents are aware of AfCFTA. The study identifies 15 factors influencing internationalization, offering one of the most comprehensive lists in this field. Hypothesis testing demonstrated that all these factors significantly affect businesses’ internationalization prospects (P < 0.001). Based on these factors, an export readiness assessment model categorizes businesses into five groups: export-ready, almost ready, midway to readiness, just starting, and preparing to start. To be considered export-ready, businesses need to score 90% or higher. Analysis of the 118 survey respondents revealed that only about 3% were fully prepared for successful and sustainable international business. Most Nigerian businesses (approximately 66%) were categorized as almost ready, which may explain the high attrition rate among new exporters due to their incomplete readiness for engaging successfully and sustainably in foreign markets.