|Full Name||William Cartwright|
|Family|| Ben Cartwright (uncle)|
|Children||Peggy Dayton (step-daughter)|
|First Episode||Return to Honor|
|Portrayed by||Guy Williams|
Will Cartwright was the nephew of Ben Cartwright. On receiving a telegram stating that Will had died, Ben went to retreive the body. Finding that Will was wounded, but alive, he was promptly taken to the Ponderosa. Will's past was basically unknown, except his for serving in the Mexican War. Will was instantly attracted to Laura Dayton; his cousin's Adam's girlfriend. When Adam demonstrated commitment issues, Laura's Aunt recruited Will in a plan to make Adam jealous. Various events led to Adam realizing what Laura meant to him and he proposed to her; breaking Will's heart. Adam, attempting to surprise Laura with their very own home, failed to set a date for the wedding and ended up unintentionally neglecting Laura as he secretly worked on their home. During this time, Will and Laura grew closer. Will, not cut out for ranching, got an offer to travel around the world and decided to leave the Ponderosa. After telling Ben, he told Laura and she realized she was in love with him. They planned to tell Adam but refrained when Adam had an accident while working on his and Laura's new home when Will and Laura drove up in a wagon unexpectedly to tell him they were in love. Adam could no longer walk and was confined to a wheelchair. Laura stayed with Adam out of guilt and Will bowed out. One day, as Will and Laura discussed the current state of events, Adam overheard them talking and kissing in the barn. He confronted Will and told him he should be with Laura, that he really was more in love with the idea of marriage than with Laura. Will felt Adam that Adam was just trying to be honorable and refused to reconcile with Laura; also feeling guilt over Adam's inability to walk. Adam realized the barrier preventing them from being happy and pushed himself to stand up and take a few steps; showing Will that he would be fine. Will and Laura reconciled and left together; to go to San Francisco while Adam looked on bittersweetly as he loved Laura enough to let her go and be with the man she truly loved.