The bacterial outer membrane (OM) functions as a protective barrier against antimicrobials and a virulence determinant. Outer membrane β-barrel proteins (OMPs) are essential components of the bacterial OM. OMPs form cylindrical structures that function as pores, substrate specific transporters, and membrane plugs. The structural stability of a β-barrel protein is largely dependent on the interactions between neighbouring antiparallel β-strands. Previously, we characterised one such interaction, the mortise-tenon joint (MTJ). Formed from the interaction between a luminal aromatic residue on one β-strand and a glycine on the adjacent β-strand, MTJs were shown to contribute to the folding and stability of the Pet autotransporter β-barrel. Here we present a high-throughput computational approach to survey the prevalence of MTJs in all OMP structures found in the PDB. In our analysis, the occurrence and location of MTJs was correlated with the biological function, size, and number of β-strands of each OMP. Our results indicated that MTJs are highly conserved within OMP families but not conserved between different OMP families. In addition, we found that β-barrels involved in the transportation of proteinaceous substrates have a high frequency of MTJs. In contrast, we observed that MTJs are under-represented in small β-barrels, which form plug structures, and in β-barrels that employ other mechanisms of stabilisation, such as oligomerisation. Lastly, we utilised our survey and in vitro refolding assays to investigate the role of MTJs in OmpF oligomerisation, a trimeric β-barrel not related to Pet. Our results are discussed in relation to the structural requirements of OMPs and the possible role of MTJs in β-barrel stability.