Typically, the mechanical behavior of CLT shear walls for lateral loads is assumed to be governed by the wall base connections such as hold-downs and angle brackets, which transfer the horizontal loads from the upper stories to the foundations. However, in a “box type” construction typology of CLT buildings, the connections between perpendicular walls contribute to the lateral response of the CLT shear walls. This study presents the results of an experimental campaign aimed at investigating the lateral performance of CLT shear walls connected to perpendicular walls by means of typical wall-to-wall connections. Two configurations of shear wall were tested: Shear Wall configuration, which considers a single CLT shear wall subjected to a horizontal load and Shear Wall connected to Perpendicular Wall configuration, which considers a CLT shear wall subjected to a horizontal load connected to a perpendicular wall. Results showed that the Shear Wall connected to a Perpendicular Wall configuration reached higher structural performance in terms of lateral stiffness and lateral capacity than single Shear Wall configuration. This increase of lateral performance is governed by the properties of the wall-to-wall connections as well as the properties of the hold downs used in the perpendicular walls. Results of this experimental study show that the perpendicular walls and wall-to-wall connections can be included in the design models of CLT shear walls subjected to horizontal loads