This work deals with the development of a coupling device for performing biaxial tensile tests with cruciform specimens. For the project, a methodology consisting of six phases was used, that is, informational design, conceptual design, preliminary design, detailed design, manufacturing and testing. Thus, the design and sizing of two coupling devices was carried out, and the model chosen for manufacturing was based on that proposed by Rohr, Harwick, and Nahme. In addition, the design, sizing and fabrication of cruciform specimens in MDF and PS, with geometry similar to that of ISO 16842:2014, was also carried out for the device validation tests. The tests were divided into 1) device stiffness