Spurred by developments in digital fabrication, there has been an increase in the application of the Integral Mechanical Attachment (IMA) technique in timber plate structures. Despite its increase in popularity, there have been very few systematic investigations of the mechanical characteristics of IMA timber-to-timber connections. Focusing on in-plane shear, the force-deformation response of Through-Tenon joints is experimentally investigated, and their overall performance is assessed. The effect of influential design parameters is studied including the material type (Kerto-Q and Beech-Q), fiber orientation (parallel and perpendicular to the loading direction), and the tab insertion angle (45 degrees, 60 degrees, and 90 degrees). Twelve specimen groups, each with five replicates are tested. For the specimens with fibers oriented parallel to the loading direction (fiber-parallel specimens), a brittle failure is observed due to early rupture in the cross layers. On the other hand, more ductile behavior is observed for the specimens with fibers oriented perpendicular to the loading direction (fiber-perpendicular specimens) due to the compression forces perpendicular to the grains. Among the Kerto-Q specimens, the ones with a 60 degrees tab insertion angle have the greatest in-plane strength. Moreover, an increase in the tab insertion angle results in a decrease in the yield deformation capacity and an increase in the slip modulus, ultimate deformation capacity, and ductility. Among Beech-Q specimens, the fiber-parallel cases and the fiber-perpendicular cases with a tab insertion angle of 60 degrees and 90 degrees have the highest in-plane strength, respectively. Also, the slip modulus increases with the tab insertion angle for the two fiber orientation cases. The ductility of the fiber-parallel Beech-Q specimens is unaffected by a change in the tab insertion angle. Overall, very small differences are observed between the yield and peak strengths and most specimens have been classified as having low ductility. (C) 2019 Elsevier Ltd. All rights reserved.