The Dark Lady is the woman to whom Shakespeare composed a portion of his sonnets. These poems are explicitly sexual in character, in contrast to those written to the "Fair Lord". It is implied that the poet and the Lady had a passionate affair, but that she was unfaithful, perhaps with the Fair Lord. The poet self-deprecatingly describes himself as balding and middle-aged at the time of the affair. The Lady hereself is referred to as 'dark' because her hair is black and her skin dusky. However, the language of the verses also strongly implies that she represents the 'dark' forces of physical lust as opposed to the ideal Platonic love associated with the Fair Lord.

Many attempts have been made to identify the Dark Lady with an historical personality, but all are highly speculative.