Shakugan no shana?third season?

Question

is there going to be a third season and when?

Answer 1

yes there is, its probably gonna come out when zero no tsukaima: princess no rondo is finished

Answer 2

There is definitely a possibility. The light novel, which began in 2002, is still being published with 19 volumes released. Both seasons so far have not given an absolute ending, thus opening the need for a continuation. There isn't any news so far but with two mangas and an OVA they've made, including a movie, there isn't any reason why the animators would drop the series at this point.