We have a lot of comic book artists here in Portugal, most of them doing underground, artsy graphic novels and comics. They're pretty much unknown outside the country, but in the right circles some of them are highly lauded and acclaimed.
As of now, out of all the major artists out here, I'd highly recommend checking
José Carlos Fernandes, especially his series
A Pior Banda do Mundo (lit. "the worst band in the world") -- French edition cover pictured.
We also have this recent amazing series called
Dog Mendonça & Pizzaboy, written by Filipe Melo, a Portuguese musician, with art by Juan Cavia, an Argentinian artist. Dog Mendonça is fast paced, amazingly written and superbly drawn, takes place mostly in Portugal but with scenes across some other European countries as well. It has been enjoying moderate success, being published in the U.S. by Dark Horse Comics, and with John Landis, Tobe Hooper and George Romero providing prefaces to the books. Be sure to check this one out.
[EDIT] Well, if any of you fine people reading this would care, be sure to browse Stuart Carvalhais, a late XIX-early XX centuries Portuguese cartoonist that was not only a precursor of the cartoon medium over here, but worldwide, as well, and tends to be forgotten in most -- if not all -- cartoon/comics histories and studies around. He has a
Portuguese Wikipedia page, that's all I could find, if you're interested just use some reliable web translator to understand it.