The need for lie detection is to resolve disputes that arise over inheritance, forgery, impersonation as well as in forensic science which deals with application of science to law aiding to deliver justice by eliciting truth, scientific evaluation of physical evidence usually encountered in many civil, criminal regulatory and statutory cases. All the methods for lie detection including the most popular polygraph testing depend on the measurement of variation of physiological conditions like heart beat rate, respiratory rate (breath rate), etc. by establishing physical contact of some medical device with the person’s body and thus are invasive and obtrusive. But these physiological conditions vary due to the effect on the autonomic nervous system (ANS) for any reason irrespective of whether the person tells a lie or the person is innocent but feels nervous for being under test. This leads to an ambiguous and/or inaccurate decision about the person telling lies. A radar based lie detector proposed recently can be a remote, non-contact, non-invasive and unobtrusive method. This review paper summarizes the common signs of deceptive behavior, major non-radar based methods used earlier and finally, the radar based technique for lie detection that has emerged as a technical breakthrough in lie detection.