text: how can i get my 3 year old daughter to stop sucking her thumb?   just wait it out - she is most likely doing it only in situations where she needs to feel 'more comforted' - perhaps you can address while she feels like that.  it's also very commonly used as a sleep aid at that age - if she's only doing it when going to sleep - i still would not worry about it at this age. let them grow up on their own terms as much as you can.  people are 'forcing' the development of their children ever earlier and earlier these days - it's sad to see.