The present invention relates to a process for purifying a pyrolysis oil comprising providing a stream S0 comprising a pyrolysis oil, the pyrolysis oil comprising one or more halogenated organic compounds and one or more organic compounds comprising conjugated double bonds; subjecting the stream S0 to hydrogenation in at least one reaction zone Z1 containing a heterogeneous hydrogenation catalyst, obtaining a stream S1 being depleted, compared to S0, in the one or more organic compounds comprising conjugated double bonds; subjecting the stream S1 to dehalogenation in at least one dehalogenation zone Z2 down-stream of Z1, obtaining a stream S2 being depleted, compared to S1, in the one or more halogenated organic compounds.