Gene therapy, i.e. the delivery and expression of therapeutic genes, holds great promise for congenitaland acquired respiratory diseases. Non-viral vectors are less toxic and immunogenic than viral vectors,although they are characterized by lower efficiency. However, they have to overcome many barriers,including inflammatory and immune mediators and cells. The respiratory and airway epithelial cells, themain target of these vectors, are coated with a layer of mucus, which hampers the effective reaching ofgene therapy vectors carrying either plasmid DNA or small interfering RNA. This barrier is thicker inmany lung diseases, such as cystic fibrosis. This review summarizes the most important advancements inthe field of non-viral vectors that have been achieved with the use of nanoparticulate (NP) systems,composed either of polymers or lipids, in the lung gene delivery. In particular, different strategies oftargeting of respiratory and airway lung cells will be described. Then, we will focus on the two approachesthat attempt to overcome the mucus barrier: coating of the nanoparticulate system withpoly(ethylene glycol) and treatment with mucolytics. Our conclusions are: 1) Ligand and physical targetingcan direct therapeutic gene expression in specific cell types in the respiratory tract; 2) MucopenetratingNPs are endowed with promising features to be useful in treating respiratory diseases andshould be now advanced in pre-clinical trials. Finally, we discuss the development of such polymer- andlipid-based NPs in the context of in vitro and in vivo disease models, such as lung cancer, as well as inclinical trials.