Few works investigate the fatigue of short fiber reinforced thermoplastics under cyclic compression. Furthermore, the heat buildup approach to quickly predict the fatigue lifetime of these materials has not yet been investigated for compression–compression loadings. This paper first describes an experimental protocol to perform well-controlled cyclic compression tests without anti-buckling device that may induced bias. The uniaxiality of the global loading is checked during the test based on kinematic and thermoelastic coupling field measurements. Then, the paper compares the results from fatigue and heat buildup tests performed on polyetheretherketone reinforced with 30 wt% of short carbon fibers for several load ratios. It is shown that the fatigue lifetime is higher in compression than in tension and depends on the compression load ratio. The heat buildup approach appears to be relevant to quickly predict the fatigue lifetime of the material for the different loading ratios studied, including compression–compression.