Trojan Cassandra, daughter of Priam and Hecuba, was amorously pursued by the god Apollo. Having at first agreed to succumb to his advances, she was awarded the gift of prophecy, but later, when she changed her mind and refused him, Apollo punished her. She would remain a prophetess, but would never be believed. Cassandra's predictions were invariably of disaster, foretelling the murder of Agamemnon by Clytemnestra or the destruction of Troy through the ruse of the Wooden Horse. A Cassandra today is anyone who utters dire warnings of the future, regardless of their truth.

(Greek mythology) a prophetess in Troy during the Trojan War whose predictions were true but were never believed

a term used to describe one that predicts misfortune or disaster

In Greek mythology, Cassandra (Greek: Κασσάνδρα "she who entangles men") (also known as Alexandra) was a daughter of King Priam and Queen Hecuba of Troy whose beauty caused Apollo to grant her the gift of prophecy. However, when she did not return his love, Apollo placed a curse on her so that no one would ever believe her predictions.

Cassandra Alexandra (カサンドラ・アレクサンドル　Kasandora Arekusandoru) is a fictional character from the Soul series of fighting games. Cassandra made her first appearance in Soul Calibur II and has returned in Soul Calibur III.

Cassandra is a fictional character from the universe of , portrayed by actress Tracy Scoggins. She is an Immortal.

In the science fiction series Stargate SG-1, Cassandra Fraiser is a young girl originally discovered on another planet, and adopted daughter of Janet Fraiser.

Cassandra was the fourth episode to air in the eighth series of Red Dwarf.