Mendacity
Lying is everywhere in this play, and Williams treats it as the root of suffering. Characters lie to protect themselves, but the lies trap them. Big Daddy's cancer, Brick's guilt, Maggie's pregnancy: every major lie eventually breaks open and does damage.
Desire and repression
Brick's feelings about Skipper are never named directly, but the play circles them constantly. Williams shows what happens when desire can't be spoken: it turns inward, becomes guilt, and destroys the person carrying it.
Money and inheritance
The plantation is worth a fortune, and every adult in the family wants a piece of it. Gooper and Mae have a legal strategy. Maggie has a lie. The competition for Big Daddy's estate forces every character to show what they're actually willing to do.
Death and denial
Big Daddy is dying, and almost no one will say it. The birthday party is built on a false diagnosis. When the truth comes out, it doesn't bring peace; it brings chaos. Williams shows denial as a survival strategy that eventually collapses.
Marriage as performance
None of the marriages in this play are what they appear. Brick and Maggie don't sleep together. Big Daddy doesn't love Big Mama. Gooper and Mae perform family harmony to win inheritance points. Williams shows marriage as something people do in front of an audience.