Imagining performing joint actions requires one to integrate one’s own imagined actions with the imagined actions of another person. In two experiments, we investigated motor imagery of joint action to determine if and how imagery processes are adapted based on the assumed motor capabilities of the partner. Participants imagined performing a joint serial transfer task (moving 4 discs to a peg) quickly and accurately with an imagined partner. Participants imagined transferring the first 2 discs in the sequence onto the target peg themselves and then imagined the partner transferring the last 2 discs. The description of the imagined partner (high vs low performer) was manipulated to determine if participants adapt their imagination based on the partner’s characteristics. Results revealed imagined MTs for the whole sequence were shorter when the description of the partner gave the impression of a ‘high’ performer compared to when the description was of a ‘low’ performer or when no description of the partner was provided. Results further revealed participants not only adjusted the imagined MTs of the partner’s portion of the task, but of their own portion of the task as well. That is, imagined MTs of the first 2 disc transfers were shorter when imagining performing the task with a high performer than with a low performer or when no description of the partner was provided. These findings suggest participants are able to adapt their imagination to the assumed capabilities of their partner, but that these adjustments also affected the imagination of their own movements.