The article discusses a vexed question of internal jurisdiction of Jewish diaspora communities in the Roman province of Asia, particularly at Sardis. The validity of Flavius Josephus’ evidence is upheld, following the arguments of E.J. Bickerman and C. Eilers, and the ideology behind Roman interventions in support of Jewish courts discussed. It is contended that the judicial privileges granted by Rome to Jewish communities in Asia Minor were meant to protect Jews from misuse of power by local, rather than Roman provincial, courts. The grant of such privileges was likely to be based on a degree of recognition by the Roman government that the «ancestral laws» of the Jews were different from those of the Greeks and, thus, on the fact of Jewish substantive law being in existence in Asia Minor. It is further argued that the view that this necessarily entailed official recognition of internal Jewish courts is unwarranted and that even at Sardis, where it is known to have been granted, Jewish privileges in the judicial sphere remained very restricted in comparison with the level of autonomy that could be enjoyed by civic courts. In conclusion, further consequences of conflict of judicial privileges between Greek and Jewish communities for the spread of Roman jurisdiction in Asia Minor are explored.