A plug-in connector arrangement comprising two plug-in connector parts (100, 200) which can be plugged into each another and which each have a housing part (101, 201), the housing parts being adapted to each another, and a plug contact (110, 210) provided therein, the plug contacts being adapted to each another, wherein the two housing parts (101, 201) have detent elements for detachably connecting the two housing parts to each other, characterized in that the detent elements comprise at least one detent tongue (300) that has a detent lug (310) and is arranged in a tongue-receiving pocket (500) in the first housing part (100), said detent lug (310) engaging in an opening (400) provided therefor in a housing wall of the second housing part (201), and in that said tongue-receiving pocket in the first housing part (101) is in the form of a groove that has a substantially U-shaped cross-section, the two lateral limbs (510, 520) of the U projecting beyond the detent tongue (300).