Like it says, it runs pretty small. I got a large, while I usually wear somewhere between a small and a medium. The large fits pretty good for me. If there was an extra-large, that might even be better. But I have to say that I LOVE how it looks!! This has become my go-to shirt, and the quality is great! Just make sure that you go 1 or 2 sizes up from your normal size.
Ordered a medium and it fits like an XS. For reference, I am 5’6, 120lbs and normally wear a small.