After reading that these ran large, I almost sized down, but I have other pairs of Wax jeans, and they all run a bit small. I'm really glad I didn't size down because even though I ordered my size, they are quite tight. They will stretch out after a few hours of wear. They look good, except the back pockets are strangely high.
For reference, I'm 5'3", and currently 138 pounds, I ordered a size 7. In most brands, I'm usually a size 5 in stretchy jeans.