In this work we provided an overview about the use of small-angle X-ray scattering (SAXS) technology for non-invasive characterisation of nanostructured and functionalised particles. Firstly, we demonstrated our modular-designed laboratory SAXS camera with different options and possibilities for quick in-situ measuring various disperse particulate systems including powders and suspensions as well as aerosol nanoparticles which can be deposited on a certain substrate. The detection angle reaches 90 degrees, allowing simultaneous wide-angle X-ray scattering (WAXS) measurement on the crystalline structures. Further extension of the sample-to-detector distance enables multi-level structural characterisation of particle systems ranging from about one nanometer to several hundred nanometers. The use of an on-line X-ray detector makes on-line in-situ analysis possible. Secondly, different data processing methods and models have been introduced for analyzing the acquired scattering data and retrieving the structural parameters of the investigated particle systems. Finally, we presented some selected experimental results obtained by SAXS-WAXS, including commercial nanoparticles, and laboratory-synthesized nanostructured and functionalised particles such as silica multiplets, silica-magnetite core-shell nanocomposites, metallic nanoparticles and catalyst nanodots on oxide support particles in different liquid- and gas-phase synthesis processes as well as nanostructured particles in particle handling processes like high pressure dispersion and high temperature calcination. (C) 2018 Institution of Chemical Engineers. Published by Elsevier B.V. All rights reserved.