Provided herein are peptidomimetic macrocycles containing amino acid sequences with at least two modified amino acids that form an intramolecular cross-link that can help to stabilize a secondary structure of the amino acid sequence. Suitable sequences for stabilization include those with homology to the p53 protein. These sequences can bind to the MDM2 and/or MDMX proteins. Also provided herein are methods of using such macrocycles for the treatment of diseases and disorders, such as cancers or other disorders characterized by a low level or low activity of a p53 protein or high level of activity of a MDM2 and/or MDMX protein.