Proving a negative or negative proof may refer to:

• Proving a negative, in the philosophic burden of proof
• Evidence of absence in general, such as evidence that there is no milk in a certain bowl
• Modus tollens, a logical proof
• Proof of impossibility, mathematics
• Russell's teapot, an analogy: inability to disprove does not prove
• Sometimes it is mistaken for an argument from ignorance, which is non-proof and a logical fallacy