Click chemistry is a widely used synthetic method due to its simplicity, efficiency, and high selectivity. This review discusses the importance of reaction rates in selecting the most suitable click chemistry reactions for biomedical applications. While reaction rates are often overlooked, they are crucial for determining the efficiency and suitability of reactions in various biomedical contexts. The review highlights the benefits and limitations of established click chemistry reactions, including cycloadditions, nucleophilic ring-opening reactions, non-aldol carbonyl reactions, and additions to carbon–carbon multiple bonds. It also discusses newer click chemistry reactions such as strain-promoted azide–alkyne cycloaddition (SPAAC), inverse electron demand [4+2] Diels–Alder (IEDDA), and strain-promoted azide–alkyne reactions of cyclopentadienones. The review emphasizes the importance of considering reaction rates when selecting click chemistry reactions for biomedical applications, as reaction rates can significantly impact the efficiency and effectiveness of the reactions. The review also discusses the application of click chemistry in various biomedical areas, including drug delivery, imaging, and bioconjugation. The review concludes that while rapid reaction rates are often desired, they are not always necessary for all biomedical applications, and the selection of the most suitable click chemistry reaction should be based on the specific requirements of the application.Click chemistry is a widely used synthetic method due to its simplicity, efficiency, and high selectivity. This review discusses the importance of reaction rates in selecting the most suitable click chemistry reactions for biomedical applications. While reaction rates are often overlooked, they are crucial for determining the efficiency and suitability of reactions in various biomedical contexts. The review highlights the benefits and limitations of established click chemistry reactions, including cycloadditions, nucleophilic ring-opening reactions, non-aldol carbonyl reactions, and additions to carbon–carbon multiple bonds. It also discusses newer click chemistry reactions such as strain-promoted azide–alkyne cycloaddition (SPAAC), inverse electron demand [4+2] Diels–Alder (IEDDA), and strain-promoted azide–alkyne reactions of cyclopentadienones. The review emphasizes the importance of considering reaction rates when selecting click chemistry reactions for biomedical applications, as reaction rates can significantly impact the efficiency and effectiveness of the reactions. The review also discusses the application of click chemistry in various biomedical areas, including drug delivery, imaging, and bioconjugation. The review concludes that while rapid reaction rates are often desired, they are not always necessary for all biomedical applications, and the selection of the most suitable click chemistry reaction should be based on the specific requirements of the application.