Alphabetize Category Pages

Hi :-) It's probably been asked before, but I can't find it - is there a way to alphabetize the products on the category pages? If it's in the settings somewhere, I can't find it.

Right now, my products display in order of being added, with the newest item first. It would be nice to be able to have all products of the same brand (Nike, Wilson, etc...) grouped together on the page.

Thanks so much in advance :-)