The Bible portrays circumcision as having an important role in Israelite culture. Consequently, circumcision has received a great deal of scholarly attention. Some have viewed it as having an “internal” role, for example, for rites of fertility and marriage, whereas others have highlighted its “external” role as an ethnic marker, differentiating the Israelites from “other” groups. Circumcision, however, was practiced by many groups in the ancient Near East, and it is commonly accepted that if circumcision was an ethnic marker, it functioned mainly against the “foreign” Philistines, who did not practice it. Interestingly, all the biblical texts that depict the Philistines as םילרע (uncircumcised) project this reality into the premonarchic period (Iron I), regardless of their date, source, or genre. Not a single text, regardless of genre, uses this pejorative to describe the Philistines in the monarchic period (Iron II). This clear-cut dichotomy is supported by additional historical and archaeological lines of evidence (direct and indirect) and is in line with other changes in Philistine culture. All this seems to suggest that the Philistines started to circumcise in Iron II, the time when they ceased to manufacture their Aegean-inspired decorated pottery, adopted the local script, changed their foodways, and so on. This, in turn, gives us a better understanding of the significance of circumcision for the Israelites, and it appears that the “internal” and “external” explanations are not mutually exclusive. Rather, they reflect different perspectives on the practice over time, as well as different views by different social fractions.