Abstract: The tool to aid in fireplace flue installation supports the sections of a flue during attachment to the vent of a fireplace or stove. The tool has a support bracket for mounting the tool to a vertical support, such as a stud in a chase where the flue will be installed. Attached to the support bracket is an arm support member, which holds a plurality of flue support arms. The flues support arms are pivotally attached to the support member so that the arms rotate about a vertical axis. Each support arm can be rotated independently of the other support arm or arms. The support arms are provided with setscrews, which are tightened to lock the support arms into a selected position. Each support arm may be provided with an arm extension, which slidably engages the support arm, allowing the overall length of the arm to be extended.