Designers favor laminated glass due to its inherent robustness. However, there is disparity between the various design codes currently available for laminated glass and the methods therein for calculating resistance to lateral-torsional buckling. This study examines the effective thickness methods found in some existing codes, which calculate the degree of composite action achieved by a laminated glass section subject to in-plane loading. These design methods are compared using relevant accompanying methods from the standards to calculate buckling loads and glass strength where appropriate to gain an understanding of how these methods are implemented in the industry. Results from the calculations are compared to published experimental data in order to assess the relative accuracy and range of applicability of each method. A parametric study is also undertaken, using results from a numerical model to predict the lateral-torsional buckling capacity of laminated glass sections with various geometries and properties. A significant range in results from the various design methods has been observed. It has also been found that some design methods give consistently nonconservative results.