The behaviour of thin-walled Z-section beam subjected to gravity load for different variants of lateral restraints is analyzed. For the basic variant of the laterally restrained beam the one defined in Eurocode 3 (EN 1993-1-3:2006) is taken. The Z-section beam which is laterally restrained along the flange by trapezoidal steel sheeting is observed, shown as a Z-section beam laterally restrained with linear stiff connection and rotary elastic connection. Variant of laterally restrained Z-section beam with a linear stiff connection, a variant of laterally restrained Z-section beam with rotary elastic connection and beam without lateral restraints are analyzed. Based on the research, analysis and comparison of the results for individual variants of thin-walled Z-section beams, with and... without lateral restraints, is conducted.