Dreaming about a girlfriend may represent your feelings and emotions towards that person, or it may symbolize your desire for a romantic relationship or for companionship in general.
If you dream that you are with your current girlfriend and the two of you are happily spending time together, it may represent your feelings of love, happiness, and contentment in your relationship. Also, the dream may be a reflection of your desire to spend more quality time with your partner in waking life.
If you dream that you are with a woman you do not know, but you feel like she is your girlfriend, it may represent qualities or characteristics that you desire in a partner. Also, the dream may be a manifestation of your unconscious desire for a romantic relationship.