The PAN Wikipedia Quality Flaw Corpus 2012, PAN-WQF-12, provides human-labeled English Wikipedia articles that contain specific quality flaws. The corpus comprises 1,592,226 articles extracted from the English Wikipedia snapshot from January 4th, 2012. A subset of 208,228 articles is labled with ten specific quality flaws, which are listed in the following table. The labeling is based on human-defined cleanup tags. In addition, the corpus comprises 1,383,998 articles that have not been tagged with any cleanup tag.