Difficult to prove whether acupuncture is placebo or not, because you can't really make a control group believe that they've been poked with needles without actually poking them with needles.
But at the very least, you are poking people with needles, so unlike homeopathy, it will have some non-placebo effect. The question is rather whether that's the medicinal effect you're trying to achieve.
Having said that, I've had acupuncture, because my mum dragged me there. I was not convinced that it'd help, yet it did reduce pain. That still does not fully exclude the possibility of a placebo effect, but it seems rather unlikely to me either way.