I have found that different people have different definitions of sweaters. To me, a sweater is a large, knitted beasty of at least a medium bulk. To my wife, just about any pull-over qualifies as a sweater, including a sweat-shirt, which I could never call "sweater."

I, for one, would never call the turtle-neck that Jamie is wearing a sweater. Apparantly there are those who do, though.

So I think our different definitions of "sweater" will lead to different answers to this question.

In general, if your definition of sweater (like mine) implies some bulk to it, I'd never wear it tucked into the kilt. However, if your definition of sweaters includes some thinner, more fitted varieites, you might do well to tuck those in, as you would any shirt.

Regarding the bulkier sweaters though, that you would wear outside your kilt, many of them have a fitted band at the bottom. I find that it helps if I bring that band up to the waistline of my kilt, and then let the sweater hang over that -- it makes the sweater look a bit shorter, and more fitting with the kilt, in my opinion.