Abstract: This technical note describes the US Army Research Laboratory (ARL) Arabic Dependency Treebank (AADT) for the purpose of documenting its release. The AADT was derived from existing Arabic treebanks distributed by the Linguistic Data Consortium using constituent-to-dependency conversion software written at ARL. Earlier versions of the AADT, as well as parsers trained from it, have been used in several published ARL research efforts, and, by releasing the data, we hope to facilitate additional Arabic language processing research by the greater community.