The legal thriller genre is a type of crime fiction genre that focuses on the proceedings of the investigation, with particular reference to the impacts on courtroom proceedings and the lives of characters.

The genre came about in the 16th century with the publication of short stories and novels based on court cases taking place at the time. Some of the novels were later adapted into early television series and film productions during the 1950s.

Many legal professionals, including Scott Turow in Presumed Innocent and Harper Lee in To Kill a Mockingbird, constitute the primary authorship of the genre, drawing on their own relevant experiences.

The legal thriller genre's courtroom proceedings and legal authorship are ubiquitous characteristics. The genre features lawyers as legal professionals as the supreme hero. Their actions in the courtroom affect the quality of character's lives, as they determine innocence prevailing against injustice.

Legal language is also another characteristic of the legal thriller in that it employs real life lawyer terminology, courtroom, and police procedures among characters. The television shows Suits and How to Get Away with Murder embody the legal thriller, characterized by episodes based on scenarios of legal proceedings similar to actual court scenarios.

Novels, films, and television series such as To Kill a Mockingbird, How to Get Away with Murder, and Marshall have received nominated for awards such as the Pulitzer Prize and NAACP Image Award for their awareness of controversial topics such as racial discrimination, gender inequality, the death penalty. The legal thriller genre has expanded to accommodate contemporary social themes while also preserving the general plot and actions of original legal thrillers.

The earliest written version of legal thrillers came in the form of plays and stories printed in the newspaper date back to the mid-1550s. One of the first authors to bring into existence the legal thriller as a genre in the 1850s was Wilkie Collins. Collins learned from another writer who took an interest in the genre known as Charles Dickens. Among the first books Collins produced included The Woman in White and The Moonstone which was among the first novels to display the storyline of a legal thriller by incorporating the testimonies of various characters to show the storyline of a detective investigating a crime, finding a suspect innocent, and generating a storyline of suspense. In the 20th Century, one of the most popular authors in legal fiction came to be Melville Davisson Post. His style of plots were notoriously fast-paced yet easy to follow as seen in his novel Corpus Delicti where he showcases a calm, collected, intelligent lawyer who advises his clients to go to extreme lengths to defend his case.

Between the 1930s-1940s, author and active lawyer, Elre Stanley Gardner, wrote a series of novels that carried out the same proceedings of a legal thrillers as those in previous novels. In 1933, he wrote The Case of the Velvet Claws starring fictional lawyer, Perry Mason, who embarks on a journey of proving the innocence of clients that has been found guilty only to find that the culprit was one of the witnesses all along.