What does it mean to dream about sphinx?
A sphinx in a dream often pictures a riddle you must answer, a guardian at a threshold, or a question about yourself that blocks the way forward.
Four ways to read it
Each reading below comes from a named tradition and a cited source, so you can see where it came from and decide what fits your dream.
Freud
Freud took the sphinx's riddle as the child's question about origins and self, the puzzle that underlies so much later searching. The figure guards a knowing both wanted and feared. Ask what question the dream set before you.
After Freud, The Interpretation of Dreams (Brill trans., 1913), public domain.Jung
Jung would see the sphinx as a guardian of the threshold, posing the riddle that must be solved before one can pass into a new stage. The answer is often self-knowledge. The dream may mark a passage that waits on what you understand about yourself.
Jungian concept (our summary).Modern
Threat-simulation theory suggests the dreaming brain can stage a guardian who bars the way until a challenge is met, mirroring a waking obstacle that demands an answer. It can follow a problem you feel stuck inside. Notice whether you faced the riddle or turned back.
Threat-simulation theory (our summary).Mythological
In Greek myth the sphinx kills those who fail her riddle until Oedipus answers it and frees the city. The Egyptian sphinx broods as a vast guardian over sacred ground. The image tends to ask what you must understand before you can move on.
Rosmerta Publishing editorial synthesis (after Bulfinch; Brewer).