This study examines the relationship between artificial intelligence (AI) adoption and organizational performance among small and medium enterprises (SMEs) in Nigeria. Drawing on the Technology–Organisation–Environment (TOE) framework and the Resource-Based View, the study adopted a cross-sectional survey design and collected data from 384 SME owner-managers across Lagos, Abuja, Kano and Port Harcourt using a structured questionnaire. Data were analysed using descriptive statistics, correlation analysis and multiple regression with partial least squares structural equation modelling (PLS-SEM). The findings reveal that AI-enabled automation, data analytics and machine learning, AI-powered customer service and AI decision-support systems jointly and significantly predict organizational performance (R² = 0.612, p < 0.001). Organisational readiness significantly moderated this relationship. High implementation cost, a persistent skills gap and unreliable infrastructure emerged as the dominant barriers. The study concludes that AI adoption is a meaningful driver of both financial and non-financial performance among Nigerian SMEs, and recommends targeted policy support, affordable AI-as-a-service models and structured digital-skills programmes.