Fiber-reinforced cementitious mortar (FRCM) is an emerging retrofit system for concrete and masonry structures. Numerous bond tests have been performed on FRCM-concrete joints, typically subjecting the interface to pure shear stresses. In some applications including flexurally loaded or curved, tapered, and arched members, the FRCM-concrete interface is typically subjected to both shear and normal (peeling) stresses creating a mixed-mode bond condition. Despite this, the effects of mixed-mode stresses are yet to be evaluated. In this study, an experimental campaign comprising twenty specimens was undertaken to evaluate the effects of mode mixity via varying the peel angle (θ) between the FRCM composite and concrete substrate. Eight θ values were investigated, namely: 0°, 2°, 4°, 8.5°, 14°, 19.3°, 26.6°, and 36.9°. Concrete blocks with dimensions of 300 × 150 × 250 mm (length × depth × width) were fabricated and bonded to a single layer of carbon-FRCM reinforcement having bond length and width of 250 and 75 mm, respectively. An approximate bilinear relationship between peak load and θ was constructed with the boundary between the two lines occurring at a virtual θ of 11.5°. As θ increased from 0° to 11.5 °, the peak load reduced by 88%. Larger angles resulted in smaller and gradual decrease in the peak load. The peel angle also had noticeable effects on the failure mode with debonding of the FRCM composite from the concrete substrate being more observed in the case of small angles, while debonding of the fiber grid from the embedding mortar governing in larger angles.