The first agreement occurs between the Green Knight and Sir Gawain with neither character disguised. At the start of the poem, the Green Knight bursts into Camelot's court during Christmastime. He offers a challenge to the knights present: to cut off his head with his ax, then to accept a return blow on their own neck the following year. At first, the knights are all too frightened to move an inch, but Sir Gawain steps up. He beheads his challenger, but the Green Knight simply picks up his own head and rides away, expecting Sir Gawain to keep his end of the bargain.

The second agreement occurs between Sir Gawain and the disguised Green Knight. The Green Knight has assumed the identity of Lord Bertilak and hosts Sir Gawain at his castle. When Bertilak goes out hunting during the day, he agrees to give his quarry to Sir Gawain, so long as Sir Gawain gives him anything he takes during his time in the castle. The exchange becomes strangely erotic: Gawain receives kisses from Bertilak's wife during the day, so he kisses Lord Bertilak whenever he returns from the hunt.

In both agreements, Sir Gawain proves less than honest. He does not give Lady Bertilak's enchanted girdle to his host after receiving it, since he hopes to preserve his life by wearing it when it is his turn to receive a blow on the neck. He essentially tries cheating the Green Knight twice.