Lies and Mendacity run rampant in Cat on a Hot Tin Roof. They help keep the play going and keep it interesting. The play shows us the lies that people tell themselves and other instead of the truth that is hard to accept but must be said.

The entire family is involved with lies to Big Daddy and Big Momma, as are the doctors. They tell them that Big Daddy does not have cancer, but only a spastic colon. Brick lies to himself about his feelings for Skipper until Big Daddy forces him to face it. He then understands that he is upset about the way his clean friendship has been misinterpreted. Gooper and Mae pretend to be loving and doting children, when in fact all they want is money and land. Big Mama lies to herself, think all the cruel things Big Daddy says are just jokes. She also lies to herself by thinking that a child from Maggie and Brick would turn Brick into a non-drinking, family man qualified to take over the family place. Big Daddy is even wrapped up in the mendacity. He admits to Brick that he is tired of letting all the lies. He has lied for years about his feelings for his wife, his son Gooper and his daughter-in-law Mae, he says he loves them, when in fact he can't stand any of them. Maggie, who seems to tell close to the truth the entire play, breaks down and lies about her pregnancy.

Sometimes the lies are not even lies; they are just seen to be that. Big Daddy thinks that Big Momma is scheming to take over the place, when in fact she really does love him. He only sees this as a lie because of his feelings toward her. Brick seems to feel them same way about Maggie, and is surprised in the end when Maggie declares her love for him.

Big Daddy and Brick are perhaps the only two that do not lie to each other. During their heart-to-heart Big Daddy says, "then there is at least two people that never lied to each other." (Act 2 p.113)

Lies show up everywhere in Cat on a Hot Tin Roof, as the play progresses the falsehoods of each character are stripped away and their true intentions come to light. Without the lies the play would lose most of its dimension.