This paper presents the results of an experimental study to examine the in-plane behaviour of the moment-resisting beam-to-column connections of thin-walled sinusoidally-corrugated web I-sections. A group of specimens of nearly full-sized beam-column assemblies made of sinusoidal corrugated web I-sections were tested under cyclic loading in the Structural and Earthquake Engineering Laboratory of Istanbul Technical University (ITU). Whereas two of the specimens have corrugated panel zones, the others have flat plate panel zones, according to an existing practice. The results of the experimental works are evaluated in terms of the general behaviour of the specimens and the regional behaviour of the panel zones. Three-dimensional nonlinear finite element analysis (FEA) models are developed in ABAQUS, including nonlinear interaction along with the contacting parts. The analytical results show a satisfactory convergence with the experimental results. The specimens that had relatively thicker flat plate webs in the panel zone were more stable than those which had corrugated web panels. (C) 2014 Elsevier Ltd. All rights reserved.