Binary pulsars can be excellent probes of ultra-light dark matter .
We consider the scenario where the latter is represented by a spin-2 field .
The coherent oscillations of the dark matter field perturb the dynamics of binary systems , leading to secular effects for masses that resonate with the binary systems .
For the range 10 ^ { -23 } eV \lesssim m \lesssim 10 ^ { -17 } eV we show that current timing data could potentially constrain the universal coupling strength of dark matter to ordinary matter at the level of \alpha \simeq 10 ^ { -5 } .