This paper addresses the use of generalized beam theory (GBT) to analyse the local and global buckling behaviour of thin-walled steel members and structural systems. After a brief historical perspective of GBT developments, the main concepts and procedures involved in performing buckling analyses are summarized in a systematic fashion. That is followed by a state-of-the-art report concerning the most recent GBT formulations and applications that have been developed to assess the buckling behaviour of members, frames and trusses with various loading and support conditions. In order to illustrate the unique modal features and show the potential of the GBT approach to buckling analysis, numerical results and a few practical applications are presented and discussed; for validation purposes, most of these results are compared with values yielded by shell finite element analyses, performed in the ABAQUS and ANSYS programs. The paper closes with a few words on the future perspectives of GBT-based buckling analysis.