It is well known that there was a substantial Jewish community in Ancient city of Ephesus, but no synagogue has yet been located with any certainty.
A basilica-like building north of the Theater Gymnasium is a possible candidate for the synagogue, based on a Jewish Lamp found here (which is the only lamp found in the building).
Another clue is an inscription in the nearby Church of Mary, which indicates there was a Synagogue in Ephesus and may indicate one in the immediate vicinity. A glass bottle with a seven-branched candlestick was discovered in the church.
Synagogue in Ephesus,Foundations of a basilica-like building that may have been one of several Synagogues known to exist in ancient Ephesus. A Jewish lamp was found on the site.
Paul preached Christianity in the synagogue of Ephesus during his first visit to that city (Acts xviii. 19); Apollos, a learned Jew from Alexandria, assisted by Priscilla and Aquila, proclaimed it in the same place (ib. xviii. 26). Paul, on his second visit, again preached in the synagogue; but when some Jews rejected his teaching, he went to preach in the private synagogue of a certain Tyrannus.
The Jews of Ephesus were completely Hellenized, and the inscriptions on the Jewish tombs found there are written in Greek: one stone commemorates a certain “Mar Maussios,” i.e., Rabbi Moses; another, a leading physician. Josephus often cites a certain Menander of Ephesus, whose history seems to have included that of the Jews. The city was the scene of the dialogue which Justin held with the Jew Tryphon (Eusebius, “Ecclesiastical History,” iv. 18).