Paranormal is a general term (coined ca. 1915–1920) that designates experiences that lie outside "the range of normal experience or scientific explanation"or that indicates phenomena that are understood to be outside of science's current ability to explain or measure. Paranormal phenomena are distinct from certain hypothetical entities, such as dark matter and dark energy, insofar as paranormal phenomena are inconsistent with the world as already understood through empirical observation coupled with scientific methodology.

Stories relating to paranormal phenomena are found in popular culture, folklore, and the recollections of individual subjects. In contrast, the scientific community, as referenced in statements made by organizations such as the United States National Science Foundation, maintains that scientific evidence does not support a variety of beliefs that have been characterized as paranormal.

“Paranormal” has been in the English language since at least 1920. It consists of two parts: para and normal. In most definitions of the word paranormal, it is described as anything that is beyond or contrary to what is deemed scientifically possible. The definition implies that the scientific explanation of the world around us is the 'normal' part of the word and 'para' makes up the above, beyond, beside, contrary, or against part of the meaning.

Para has a Greek and Latin origin. Its most common meaning (the Greek usage) is 'similar to' or 'near to', as in paragraph. In Latin, para means 'above,' 'against,' 'counter,' 'outside,' or 'beyond'. For example, parapluie in French means 'counter-rain' – an umbrella. It can be construed, then, that the term paranormal is derived from the Latin use of the prefix 'para', meaning 'against, counter, outside or beyond the norm.'

Experimental investigation of the paranormal has been conducted by parapsychologists. Although parapsychology has its roots in earlier research, it began using the experimental approach in the 1930s under the direction of J. B. Rhine (1895–1980). Rhine popularized the now famous methodology of using card-guessing and dice-rolling experiments in a laboratory in the hopes of finding a statistical validation of extra-sensory perception.

In 1957, the Parapsychological Association was formed as the preeminent society for parapsychologists. In 1969, they became affiliated with the American Association for the Advancement of Science. That affiliation, along with a general openness to psychic and occult phenomena in the 1970s, led to a decade of increased parapsychological research. During this time, other notable organizations were also formed, including the Academy of Parapsychology and Medicine (1970), the Institute of Parascience (1971), the Academy of Religion and Psychical Research, the Institute for Noetic Sciences (1973), and the International Kirlian Research Association (1975). Each of these groups performed experiments on paranormal subjects to varying degrees. Parapsychological work was also conducted at the Stanford Research Institute during this time.

With the increase in parapsychological investigation, there came an increase in opposition to both the findings of parapsychologists and the granting of any formal recognition of the field. Criticisms of the field were focused in the founding of the Committee for the Scientific Investigation of Claims of the Paranormal (1976), now called the Committee for Skeptical Inquiry, and its periodical, Skeptical Inquirer. Eventually, more mainstream scientists became critical of parapsychology as an endeavor, and statements by the National Academies of Science and the National Science Foundation cast a pall on the claims of evidence for parapsychology. Today, many cite parapsychology as an example of a pseudoscience.

Though there are still some parapsychologists active today, interest and activity has waned considerably since the 1970s. To date there have been no experimental results that have gained wide acceptance in the scientific community as valid evidence of the paranormal.

Scientific skeptics advocate critical investigation of claims of paranormal phenomena: applying the scientific method to reach a rational, scientific explanation of the phenomena to account for the paranormal claims, taking into account that alleged paranormal abilities and occurrences are sometimes hoaxes or misinterpretations of natural phenomena. A way of summarizing this method is by the application of Occam's razor, which suggests that the simplest solution is usually the correct one. The standard scientific models gives an explanation for what appears to be paranormal phenomena is usually a misinterpretation, misunderstanding, or anomalous variation of natural phenomena, rather than an actual paranormal phenomenon.

The Committee for Skeptical Inquiry, formerly the Committee for the Scientific Investigation of Claims of the Paranormal (CSICOP), is an organisation that aims to publicise the scientific, skeptical approach. It carries out investigations aimed at understanding paranormal reports in terms of scientific understanding, and publishes its results in its journal, the Skeptical Inquirer.

Former stage magician James Randi is a well-known investigator of paranormal claims. As an investigator with a background in illusion, Randi feels that the simplest explanation for those claiming paranormal abilities is often trickery, illustrated by demonstrating that the spoon bending abilities of psychic Uri Geller can easily be duplicated by trained stage magicians. He is also the founder of the James Randi Educational Foundation and its million dollar challenge offering a prize of US $1,000,000 to anyone who can demonstrate evidence of any paranormal, supernatural or occult power or event, under test conditions agreed to by both parties.

While the validity of the existence of paranormal phenomena is controversial and debated passionately by both proponents of the paranormal and by skeptics, surveys are useful in determining the beliefs of people in regards to paranormal phenomena. These opinions, while not constituting scientific evidence for or against, may give an indication of the mindset of a certain portion of the population (at least among those who answered the polls).

One survey of the beliefs of the general United States population regarding paranormal topics was conducted by the Gallup Organization in 2005. The survey found that 73 percent of those polled believed in at least one of the ten paranormal items presented in the survey. The ten items included in the survey were: extrasensory perception (41% held this belief), haunted houses (37%), ghosts (32%), telepathy (31%), clairvoyance (26%), astrology (25%), communication with the dead (21%), witches (21%), reincarnation (20%), and channeling spiritual entities (9%). These items were selected as they "require the belief that humans have more than the 'normal' five senses." Only one percent of respondents believed in all ten items.

Another survey conducted in 2006 by researchers from Australia's Monash University sought to determine what types of phenomena people claim to have experienced and the effects these experiences have had on their lives. The study was conducted as an online survey with over 2,000 respondents from around the world participating. The results revealed that around 70% of the respondents believe to have had an unexplained paranormal event that changed their life, mostly in a positive way. About 70% also claimed to have seen, heard, or been touched by an animal or person that they knew was not there; 80% have reported having a premonition, and almost 50% stated they recalled a previous life.

Polls were conducted by Bryan Farha at Oklahoma City University and Gary Steward of the University of Central Oklahoma in 2006, and compared to the results of a Gallup poll in 2001. They found fairly consistent results.