Peptide therapeutics have emerged as a promising approach in cancer treatment due to their high specificity, tolerable safety profile, and ability to target various aspects of cancer development, detection, and treatment. Peptides, composed of amino acids linked by amide bonds, are well-tolerated and can serve as both diagnostic and therapeutic agents (theragnostics). Over 100 peptide drugs are currently on the global market, with more than 150 in clinical development and 400–600 in preclinical studies. The FDA has approved numerous peptide-based anticancer drugs, including prostate-specific membrane antigen (PSMA) antagonists, peptide receptor radionuclide therapy (PRRT), somatostatin analogs, antibody–drug conjugates (ADCs), and gonadotropin-releasing hormone (GnRH) analogs. These drugs are used in various applications, including imaging, targeted therapy, and treatment of cancers such as prostate cancer, neuroendocrine tumors, and lymphomas. Peptides are synthesized using methods like solid-phase peptide synthesis (SPPS) and have been shown to be effective in targeting cancer cells through various mechanisms, including binding to cell surface receptors and delivering therapeutic agents. The development of these peptides has been driven by advancements in synthetic methods and a growing understanding of their biological functions. FDA-approved peptides include PSMA antagonists like 68Ga-PSMA-11, Piflufolastat F 18, Pluvicto, and Flotufolastat F 18, PRRT agents like Depreotide, 68Ga-DOTATATE, [177Lu-DOTA-TATE (Lutathera)], 68Ga-DOTATOC, and 64Cu-DOTATATE, somatostatin analogs like Octreotide and Lanreotide, ADCs like Enfortumab Vedotin-Ejfv, Polatuzumab Vedotin-Piiq, Fam-Trastuzumab Deruxtecan-Nxki, Belantamab Mafodotin-Blmf, and Tisotumab Vedotin-Tftv, and GnRH analogs like Goserelin, Leuprolide, Nafarelin, Trelstar, and Histrelin. These peptides have demonstrated significant efficacy in cancer treatment, contributing to improved survival rates and offering new therapeutic options for patients.Peptide therapeutics have emerged as a promising approach in cancer treatment due to their high specificity, tolerable safety profile, and ability to target various aspects of cancer development, detection, and treatment. Peptides, composed of amino acids linked by amide bonds, are well-tolerated and can serve as both diagnostic and therapeutic agents (theragnostics). Over 100 peptide drugs are currently on the global market, with more than 150 in clinical development and 400–600 in preclinical studies. The FDA has approved numerous peptide-based anticancer drugs, including prostate-specific membrane antigen (PSMA) antagonists, peptide receptor radionuclide therapy (PRRT), somatostatin analogs, antibody–drug conjugates (ADCs), and gonadotropin-releasing hormone (GnRH) analogs. These drugs are used in various applications, including imaging, targeted therapy, and treatment of cancers such as prostate cancer, neuroendocrine tumors, and lymphomas. Peptides are synthesized using methods like solid-phase peptide synthesis (SPPS) and have been shown to be effective in targeting cancer cells through various mechanisms, including binding to cell surface receptors and delivering therapeutic agents. The development of these peptides has been driven by advancements in synthetic methods and a growing understanding of their biological functions. FDA-approved peptides include PSMA antagonists like 68Ga-PSMA-11, Piflufolastat F 18, Pluvicto, and Flotufolastat F 18, PRRT agents like Depreotide, 68Ga-DOTATATE, [177Lu-DOTA-TATE (Lutathera)], 68Ga-DOTATOC, and 64Cu-DOTATATE, somatostatin analogs like Octreotide and Lanreotide, ADCs like Enfortumab Vedotin-Ejfv, Polatuzumab Vedotin-Piiq, Fam-Trastuzumab Deruxtecan-Nxki, Belantamab Mafodotin-Blmf, and Tisotumab Vedotin-Tftv, and GnRH analogs like Goserelin, Leuprolide, Nafarelin, Trelstar, and Histrelin. These peptides have demonstrated significant efficacy in cancer treatment, contributing to improved survival rates and offering new therapeutic options for patients.