In this article, a novel 110–170 GHz balanced tripler is presented with high‐efficiency and high‐power handling. To implement the proposed tripler, a multilayer multiplier scheme is introduced with two‐layer parallel metal fin line transitions and four planar diodes based on spatial power combining concept. Fin line transitions are used to constitute two‐layer ridge waveguides. They divide the input signal to diodes with the same amplitude and combine the third harmonic with output waveguide. The proposed tripler eliminates the dielectric loss and has good balancing characteristic, which enable the tripler to get fabulous performances such as high power handling, high‐efficiency, excellent spectral purity, and so on. The measured results shown that the tripler achieves an efficiency of 5.7%–7.8% with 147–208 mW input power and its power handling is more than 0.5W.