This article presents a meta-analysis of the effects of examiner familiarity/unfamiliarity on children's performance during individual testing. Data came from 22 controlled studies involving 1489 subjects. In a typical study, the effect of examiner familiarity raised test performance by .35 standard deviations. Differential performance favoring the familiar examiner condition was greater when subjects: (1) were of low socioeconomic status; (2) were tested on comparatively difficult tests; and (3) knew the examiner for a relatively long duration. The relationship of familiarity to examinee's handicapped status was not clear. The effects of examiner familiarity demonstrate the importance of contextual factors in testing and question the positivistic view that the test instrument is the single most important variable determining test performance. (Author/BS)