Carpentry joints, transmitting forces between timber members by direct contact and friction, were the key-elements of traditional timber construction. Often, such joints were reinforced with metal devices with the aim at avoiding disassembly under exceptional, but undefined and not quantified, loading conditions. Currently, interventions performed to improve carpentry joints are still largely based on empirical state-of-practice schemes, or on simplified assumptions on their behaviour, without explicit reference to seismic conditions. The elastic and post-elastic behaviour of the most widely adopted joints for monotonic and cyclic load has been the object of an extended research program. Results have permitted to define general criteria for the seismic improvement or strengthening of these connections.