Abstract: Torsion spring tensioning tool for tensioning a torsion spring of a counterbalancing mechanism of an overhead door, wherein the torsion spring tensioning tool comprises a housing, a gear wheel arrangement adapted to be mounted on a shaft of a the counterbalancing mechanism, said gear wheel arrangement comprising a gear wheel rotatably arranged in the housing, the torsion spring tensioning tool further comprising a gear mechanism coupled to the gear wheel for rotating said gear wheel. The gear wheel arrangement comprises a fixating arrangement fix to the gear wheel and adapted engage the shaft of the counterbalancing mechanism and transmit a rotational movement from the gear wheel to the torsion spring.