EFTCAMB patches the public Einstein-Boltzmann solver CAMB (ascl:1102.026) to implement the Effective Field Theory approach to cosmic acceleration. It can be used to investigate the effect of different EFT operators on linear perturbations and to study perturbations in any specific DE/MG model that can be cast into EFT framework. To interface EFTCAMB with cosmological data sets, it is equipped with a modified version of CosmoMC (ascl:1106.025), EFTCosmoMC, to create a bridge between the EFT parametrization of the dynamics of perturbations and observations.