The Igbo Apprenticeship Model (IAM) has long been recognized as a vital mechanism for entrepreneurial skill development and SME sustainability in southeaster Nigeria. This study examines the influence of IAM on sustainable skill specialization among registered SME operators in Anambra State. The specific objectives include: (i) identify the degree to which mentorship program sustains skill specialization among SME operators in Anambra State, and (ii) determine the extent to which cluster training model enhances skill specialization among SME operators in Anambra State. A survey research design was adopted, with data collected from 250 respondents using a structured questionnaire. Analysis was conducted using Pearson correlation via SPSS version 25. Findings revealed significant positive mentorship programs sustains skill specialization (r = 0.662, p < 0.05) and between cluster training models sustains skill specialization (r = 0.699, p < 0.05). The study concludes that mentorship and cluster training significantly enhance entrepreneurial skills and SME sustainability. It recommends the formalization and strengthening of apprenticeship programs to maximize skill acquisition and economic impact.