Does a glass table need tevila?

No, a glass table does not need tevila.

If one doesn’t put food directly on it then if for sure doesn’t need tevila. However, if one does put food directly on it then there is a discussion in the poskim as to whether it needs tevila, although the consensus of many poskim is that we do not need to be tovel our tables, see the following sources.

Sefer Tevilat Keilim (Cohen, ch. 11 halacha 302) in the name of Rabbi Shlomo Zalman Auerbach, Shut Chayei Halevi (vol 5 66, 7). Although see Shiurei Halacha from Rabbi Felder (tevilat keilim ch. 10 halacha 4) and Sefer Mishmeret Habayit (ch. 3 halacha 15) that require tevila if food is put directly on it.