My research topic is Cross-Border AI Licensing and Royalty Classification: Rethinking International Tax Rules for API Access, Model Licensing, and AI-Driven Services. AI companies increasingly monetize their technology through API access, model licensing, subscription-based services, and usage-based pricing. These models generate cross-border payments that do not fit neatly within treaty categories such as royalties, technical services, or business profits. Existing treaty wordings were drafted for static, human-led software and location-based value creation, not for automated inference, cloud-based model delivery, or AI-generated outputs. As a result, tax authorities struggle to determine whether payments for AI model access constitute use of copyright, use of equipment, automated digital services, or a hybrid category not contemplated by current treaties. Divergent OECD and UN approaches and AI's reliance on distributed server infrastructure further increase interpretive uncertainty and the risks of double taxation/non-taxation, and tax planning based on contractual structuring or server location. Against this backdrop, the dissertation develops a doctrinal framework for classifying cross-border AI-related payments. Paper 1 analyses the legal nature of Income arising from AI models by proposing a taxonomy of AI-related rights—model weights, training data rights, inference rights, and deployment rights—and assessing whether API access is “use of copyright,” whether inference is “use of equipment,” whether fine-tuning transfers IP, and whether AI outputs qualify as automated services. Paper 2 evaluates the limits of the OECD and UN Model Conventions for income arising from AI models by analysing the relevant treaty articles and their applicability to modern AI transactions. Paper 3 proposes new treaty provisions for AI-based transactions, examining whether a dedicated article is needed, how taxing rights should be allocated, and how to prevent double (non) taxation. The Introduction will present the context, article summaries, and methods. Together, the papers provide a unified framework for future treaty reform.