Originally Posted by
Penguinmoon
I'm an US passport holder, and frequent travel with a non US Passport holder. There are SOME airports that he has to have what is called a transfer visa (he doesn't pass thru immigration either) to be allowed to board flight to connecting city. As each city in the world is different for each nationality, I would contact a Malaysian Embassy to ask for sure. You won't get very far at checkin if you say well some guy on Flyertalk told me I didn't need one.
You can check the visa information on Timatic and that is what the airline employees use at checkin.
There seems to be several airlines/alliances offering the service, but I find the star alliance one the best.
http://www.staralliance.com/en/services/visa-and-health
And as an Indian transfer passenger, OP's sister does not need a transit visa.