Systems and methods for a tunable RF synthesizer based on offset optical frequency combs is provided herein. An exemplary system includes two lasers, a first laser generating a first laser output and a second laser generating a second laser output; and a coupler that receives the first and second laser outputs. Further, the system includes a resonator having first and second sections coupled to one another, the coupler coupling the first and second laser outputs into the resonator; a splitter that couples the first section to the second section, the splitter splitting a first proportion of the first laser output and a second proportion of the second laser output onto different paths within the resonator; and a controller that controls the splitter to change a size of the first proportion in relation to the first laser and the second proportion in relation to the second laser.