This chapter discusses the so-called Good Treatment Thesis in relation to slavery in the Sulu Sultanate, southern Philippines, during the first years of the American colonial period from 1899. Up until 1902, virtually all official assessments of Sulu slavery emphasized its mild and benign character, but the perception changed abruptly in the middle of 1902. This was because of greater American understanding of Sulu society, including non-elite perspectives; the increased push for economic and social reform in the southern Philippines after the end of the Philippine–American War; and the formal abolition of slavery in the Philippines by the United States Congress in July 1902.