The mechanical response of printed dog-bone specimens of poly(3-hydroxybutyrate-co-3-hydroxyhexanoate) (PHBH) in linear and nonlinear regimes is investigated. Fused filament fabrication (FFF), also regarded as fused deposition modeling (FDM), is adopted to manufacture the PHBH elements. A compressible Mooney–Rivlin constitutive law is back fitted onto digital image correlation (DIC) data, as well as uni-axial tensile test data. Effective mechanical properties are given, which may be used to design and optimize the response of printed structures. Strain values at the verge of failure in tension are also experimentally obtained. Results are especially useful for modeling mechanical response of PHBH, which is an emerging biopolymer with promising application fields in biomedical engineering, through additive manufacturing techniques.