The interest in the production of microwave passive components with the methods of additive manufacturing has increased day by day. The most important advantages of these methods are to produce microwave passive components having complex geometry in short time, low weight and low cost. In this study, rectangle waveguide power dividers at 12 GHz operating frequency are designed and produced via 3D printing and a total of 20 μm non-electrolytic and electrolytic copper plating is made on all surfaces. ABS thermoplastic as material and fused deposition modeling technique as a method are used. The novelty of this work is not only the manufacturing of T-junction component by means of 3D printing technology by using ABS termoplastic and copper plating but also, having the performance results of T-junction components with different power ratios comparatively. Return losses, transmission losses and electric field distributions of the proposed components are obtained by using CST Microwave Studio software. Rectangular waveguide power dividers having different power ratios are designed and their performances are investigated. When the results are examined, the transmission coefficient of the power divider having equal power ratio is ~3 dB in the entire frequency range. For other cases, it is observed that the phase difference and the power ratio between the output ports change depending on the frequency. The return losses in all cases are very close to each other.