A reversible ratchet wrench includes a drive shank having a support base, an open shell pivotally mounted on the support base, a ratchet wheel having a plurality of ratchet teeth, a pawl member having a sliding face slidably mounted on the support base and a toothed engaging face meshing with the ratchet teeth, and a cover to cover the ratchet wheel, the pawl member and the support base of the drive shank. The shell is pivoted relative to the support base to change the operation direction of the ratchet wheel. Thus, the user only needs to hold and pivot the shell relative to the support base to change the operation direction of the ratchet wheel, so that the user can change the operation direction of the ratchet wheel easily and quickly.