The Thai Student Loans Scheme (SLS) operation has been questioned for many years regarding its implementation performance. It satisfies many clients, but some not all. A critical problem was discovered when deferred debts (DD) were found as a cause of rising administrative costs at the SLS. So the Thai SLS still requests increasingly high national budget allocations year after year. What actually is the performance of Thai SLS operations, what are the key success factors in implementation, and what causes the DD? These questions are analyzed and ...