They have a very similar meaning! "Get dressed" is a colloquial, more common way to say "put on your clothes. It comes from "get dressed up" - which is what people do when they're going out to a fancy event - like a dance, a fancy dinner, a party, etc. Now people just say "I'm getting dressed" in a variety of situations - like when you're getting ready for your day. "Put your clothes on" sounds more stiff and formal.

They mean the same thing :) Although, "get dressed" can also mean to put on different clothes. If I am wearing pajamas and I want to go to the store, I would say "I need to get dressed". to get dressed can mean to put on clothes that are appropriate for the occasion, but it still means to put on clothes. Alexis