Coined by University of Colorado librarian, Jeffrey Beall, predatory publishers are those that exploit authors for monetary gain without regard for the scholarship or accuracy of the research they publish, often misrepresenting themselves as well-established or respected publishers. Up until January of 2017, Beall hosted a blog listing of such publishers which can be access via Internet archive at https://web.archive.org/web/20170112125427/https://scholarlyoa.com/publishers.
Contact your department's Library Liaison for a second (or first) opinion about the authenticity of a publisher or journal. We're happy to help authors identify reliable, quality scholarly publishing venues.
Use the following checklist, provided by Declan Butler in Nature, as a guide for assessing publishers and journals:
How to perform due diligence before submitting to a journal or publisher.