"Gatsby's green light: Located at the end of the Buchanans' dock, this green light represents Gatsby's ultimate aspiration: to win Daisy's love. Nick's first vision of Gatsby is of his neighbor's trembling arms stretched out toward the green light (26). Later, after Daisy and Gatsby's successful reunion, a mist conceals the green light, visibly affecting Gatsby. Nick observes, "Possibly it had occurred to him that the colossal significance of that light had now vanished forever....Now it was again a green light on a dock. His count of enchanted objects had diminished by one" (98). This image suggests Gatsby realizes he must face the reality of Daisy, rather than the ideal he created for her."
The green light is, in a sense, hope. Hope for all dreams to come true. Hope that we may have true love. In Gatsby's case, hope, for him, is that Daisy still love him. After longing for her for some many years and finally being so close to her but not being able to actually have her that green light is a symbol of his longing lasting love her Daisy. Based on what was just stated above you could say that the green light is a sybol of true love as well.
The green light is located at the end of Daisy's dock. Gatsby reaching out to it and not being able to reach it is like him being able to see his dream but not being able to fulfill it. When he looks at it, it is like he is looking the future where he see's him and Daisy together. In his vision of the future he happy and in love with Daisy, that is his Amercian Dream. In that sense the green light can also symbolize the American Dream. The thing everyone wants out life but sadly some never get.