Summary: An instance-dependent commitment (IDC) scheme takes an instance in a promise problem as public input at each time of committing and separately achieves statistical hiding and statistical binding when the instance is from different subsets of the promise. In this paper, we define a new security property called “instance-non-malleability” for the IDC. It requires the non-malleability of the instances as well as the committed messages. Instance-non-malleability is not only stronger than previous definitions of non-malleability for commitments, but can be achieved in the standard model as well. We also present a general construction of the non-interactive instance-non-malleable IDC.