Android Pay may be launching inside of Canada soon, as the most recent update (version 1.7 of the app) seems to list strings of code that include references to Interac, which is a major interbank network in Canada. Although this doesn't give any details, such as which banks may support Android Pay following a Canadian launch, the strings that mention Interac do suggest that at least some banking institutions will be adding support for the mobile payment platform in the near future. Having said that, it's quite likely that a large number of the most major banks and credit unions in the region will be adding support to their debit cards as Interac is used by many of them for debit payment processing.
Potential banks and credit unions that could be included as the first institutions to add support for the Android Pay platform are TD Canada Trust, RBC, BMO, Scotiabank and more. At this point in time, Android Pay has been live in the US since last year, slowly but surely expanding its list of the supported banks and credit unions by updating the app what seems like once a month. When it eventually reaches Canada there's no reason to suggest that Google won't be working with banks up there just as quickly to get it rolled out to everyone as soon as they can. Having said that the length of time it takes to get it working on most banks and credit unions in the country could take some time as Google is still working to get more support added in the US.
While Android Pay may be adding support for the service for Canadian users soon, Google has also taken some stuff away from Android Pay, as it was reported back on October 4th that they would be removing support for some credit and debit cards. This removal of support only applied to older cards, however, which were previously usable for tap and pay that were supported by the old Google Wallet app, which means it won't affect any of the cards which officially received support through Android Pay since it launched.