Common grounds for contesting a will in Queensland include:

1. Lack of Testamentary Capacity: The testator did not have the mental capacity to understand the nature and consequences of making the will.
2. Undue Influence: The testator was coerced or improperly influenced by someone to create or alter the will in their favor.
3. Improper Execution: The will was not executed according to the legal requirements, such as lacking the necessary signatures or witnesses.
4. Fraud or Forgery: The will or parts of it were created or altered fraudulently.
5. Revocation: The will was revoked by a subsequent will or other legal means.