The global BPO market thrives on technology, cost reduction, and specialized needs. AI and automation boost efficiency, reduce errors, and enhance the customer experience (CX) through tools like AI chatbots and data analytics. Consequently, firms are strengthening social media and online engagement as demand grows for BPO services in tech support, cybersecurity, and data analysis. This study uses the AHP method to analyze partner selection criteria in the Japanese BPO market, identifying four main factors: execution capability, experience, status, and relations, along with 16 sub-factors derived from prior research and Focus Group Interviews (FGI). Surveys of 13 BPO providers and 13 clients revealed different priorities. Providers prioritize execution, relations, status, and experience as key factors, with problem-solving, personnel competence, talent development, and management as important sub-factors. In contrast, clients value execution, experience, relations, and status. Their key sub-factors are client project experience, problem-solving, similar project experience, and strategic understanding. This research analyzes these priority gaps to offer practical strategies for aligning expectations. The findings aim to guide successful BPO partner selection and contribute to market growth.