The thermal conductivity of donor and acceptor graphite intercalation compounds is studied at high magnetic fields in order to separate the electronic from the lattice contribution. Measurements are reported in fields up to 15 T at temperatures from 2 to 50K. For one dilute sample of both a donor and an acceptor compound, the electronic and lattice contributions to the thermal conductivity are separated over almost the entire temperature range up to 50K. The temperature dependence of the electronic and lattice contributions is discussed qualitatively.