This book constitutes the refereed proceedings of the 6th International Conference on Logical Aspects of Computational Linguistics, LACL 2011, held in Montpellier, France, in June/July 2011. The 18 revised full papers presented were carefully reviewed and selected from 31 submissions. The papers address a wide range of logical and formal methods in computational linguistics such as type-theoretic grammars, dependency grammars, formal language theory, grammatical inference, minimalism, generation, and lexical and formal semantics.