Is it authentic that most of the Dajjal's followers will be Jews? Does this mean by the time the Dajjal comes, most of the kafirs will be Jews, because assuming most of the world follows him that means most of the kafir world must have been Jews. Right now Jews are only a tiny portion of the world's population.

All perfect praise be to Allah, The Lord of the Worlds. I testify that there is none worthy of worship except Allah, and that Muhammad is His slave and Messenger.

It is stated in an authentic Hadeeth that the Dajjaal (Antichrist) will be followed by seventy thousand Jews from Isfahan (in present-day Iran). It was narrated on the authority of Anas ibn Maalik that the Messenger of Allah said: “The Dajjaal will be followed by seventy thousand Jews of Isfahan dressed in Tayaalisah (sing. Taylasaan; a Persian mantle or shawl).” [Muslim]

As for the fact that most of his followers will be from the Jews, this was explicitly stated in a long inauthentic Hadeeth cited in Musnad Ahmad, which states: “…and most of his followers will be Jews and women…” Shu‘ayb Al-Arnaa’oot said: “This narration has a problem in its chain of narration.” [End of quote]

Even if we assume that this Hadeeth is authentic, the reference to ‘majority’ here does not necessarily mean the majority of people on earth; rather, it refers to the majority of people in some of the places he will go to. According to another Hadeeth, most of the people who will come out to him from Madeenah will be women. It was narrated on the authority of Ibn ‘Umar – with a chain of narration which is not sound as well – that the Prophet said: “The Dajjaal will come to this barren place in Marriqanaah (a valley on the outskirts of Madeenah), and most of those who would come out to him would be women, so much so that a man would go back to his wife, mother, daughter, sister, and paternal aunt to tie them up tight, fearing that they might go out to him…”

Allah Knows best.