My wife is a Bangaladeshi who has a Bangaladesh passport whereas I am from Sri Lanka and I have a Sri Lankan passport .We are newly married and we reside in Colombo. My wife is considering applying for a student visa in Canada and I will join her as a dependent. Will there be any issues in applying since we have two different nationalities?
Having different nationalities are not a problem in itself, as long as you are legally married according to the local law and the relationship is not excluded by Canadian immigration law (spouses/partners under 18 or virtual marriages) and she is legally residing in Sri Lanka.
Both of you will need to follow the rules for applicants from Sri Lanka, and some documents may need to be authenticated or notarized depending on the instructions from the visa office.
Other considerations apply whether you have different nationalities or not, e.g. financial ability to support both of you in Canada, genuineness of the marriage. Newly married transnational couples may have a harder time to prove a genuine marriage, but this will not usually be a problem unless you just married a month ago without having met physically with her before.