The shear lag phenomenon has been studied for open structural sections and its influence on connection capacity is included in current codes. However, for tubular gusset plate connections the differences between experimental work and predictions generated from the application of formulae from open sections have indicated the need to undertake further research. An experimental program was initially undertaken to investigate the influence of shear lag on the capacity of such connections. A total of 13 connections were tested using circular and elliptical Hollow Structural Sections (HSS). Both slotted gusset plate-to-tube and slotted tube-to-gusset plate type connections were examined, as well as both tension and compression axial loading conditions. A Finite Element analysis of these connections has been undertaken using ANSYS. A nonlinear time step analysis was performed considering nonlinear material properties. A maximum equivalent strain was defined as the failure criterion, with activation of a "death feature" of the elements. The results from the numerical analysis compared favourably with the experimental work, to hence validate the use of the FE models in a parametric analysis.