It is our pleasure to present the papers from the 20th International Workshop on Languages and Compilers for Parallel Computing For the past 19 years, this workshop has been one of the primary venues for presenting and learning about a wide rangeof currentresearchin parallelcomputing. We believe that tradition has continued in this, the 20th year of the workshop. This year, we received 49 paper submissions from 10 countries. About a quarter of the papers (12 out of 49) included authors from industry. We selected 23 papers to be presented at the workshop, for an acceptancerate of 47%, which was similar to that of the last two years. Each paper received at least three reviews, with about two-thirds of the papers getting four or more reviews each. Most papers also received at least one review from an external reviewer. The committeeheldafull-dayteleconferencetodiscussthereviewsandselectpapers. ProgramCommittee memberswho had a con?ict with a paper left the call when that paper was being discussed. There were seven submissions that included ProgramCommittee members as co-authors. These papers were evaluated more stringently and four of seven were accepted. Theworkshopthis yearalsoincludedtwoexcitingspecialevents.First, David Kirk, Chief Scientist of nVidia and a member of the National Academy of En- neering, gaveakeynotetalkonusinghighlymultithreadedgraphicsprocessorsfor accelerating general-purpose parallel computing applications. Kirk and nVidia have led the drive to make the high parallelism in graphics processors more e- ilyaccessibleforawiderangeofapplicationsbeyondtraditionalgraphicsproce- ing, andthistalkgaveLCPCattendeesavaluableperspectiveonthepotentialof thisw