The present invention is directed to a fracturing tool anchor adapted for use with a work string in a wellbore. In one embodiment, the anchor has a housing with a central passage and an uphole and downhole end. The housing has a plurality of ports positioned circumferentially around the housing and along the length of the housing. The ports each contain an engagement member, such as a piston, and a return spring. The engagement member is adapted to extend radially outward when the anchor is pressure activated, to engage the wall of the casing or wellbore. The present application is also directed to a fracturing tool anchor that does not need to be pressure activated and utilizes slips as the engagement members.