Illicit drug-related incidents such as traffic accidents and sexual assaults are gaining epidemic proportions worldwide. Besides, there is the rampant use of drugs at some critical workplaces, which can result in serious safety breaches. As a result, point-of-care diagnostic and monitoring devices are becoming increasingly important for clinical diagnostics, onsite investigation of crime, workplace testing of personnel, and roadside drug detection to prevent driving under the influence. This review focuses on the recent state of rapid and real-time diagnostics of the most common illicit drugs such as cocaine (COC), tetrahydrocannabinol (THC), methamphetamine, amphetamine, fentanyl, opioids (morphine, codeine), heroin, and benzodiazepine (alprazolam, chlordiazepoxide, diazepam, oxazepam, and clonazepam), using colorimetric, fluorescence, Raman spectroscopy, electrochemical, and lateral flow assay (LFA). It also discusses the possible evolution of some of these techniques for the rapid detection of drugs at ultra-low levels, thereby giving an insight into the future of sensor technology.