A steel beam may be strengthened in flexure by bonding a carbon fibre-reinforced polymer (CFRP) plate to the tension face. Existing studies have revealed that debonding of the CFRP plate from the steel substrate is one of the main failure modes in such CFRP-strengthened steel structures. An accurate bond-slip model for the CFRP-to-steel bonded interface is thus of fundamental importance to the accurate modeling of debonding failures in CFRP-strengthened steel structures. This paper presents two new bond-slip models for CFRP-to-steel interfaces bonded with linear adhesives on the basis of a recent experimental study by the authors. The predictions of the proposed models are compared with the test results and those of an existing bond-slip model.