Detection of differential item functioning (DIF) is most often done be
tween two groups of examinees under item response theory. It is someti
mes important, however, to determine whether DIF is present in more th
an two groups. In this article we present a method for detection of DI
F in multiple groups. The method is closely related to Lord's chi-squa
re for comparing vectors of item parameters estimated in two groups. A
n example using real data is provided.