连环杀手，又称连续杀人犯，是一个或多个杀手把受害者一个又一个地杀害，多数是谋杀。在现代城市中，杀手之心理常常被认定是变态心理，也可能是精神疾病发作，或对目标人性物化，爱操纵目标人物的生命，视目标人物如蝼蚁，可能有性欲，或道德观极端化而自命为判官，「替天行道」，有牺牲自己以达成梦想的心态。

一般的人总认为连环杀手外观必定像疯子或狂人一般，品德低劣，事实上未必，连环杀手外表多半与一般人无异，甚至很迷人，并且有高尚的情操或严格的道德感，甚至不乏高学历者，（著名的连环杀手泰德·邦迪即是最好例子），也给人他们很容易亲近的错觉。简单的说就是绝大部分连环杀手在被捕之前几乎都不会让人把他们跟他们的行为联想在一起，当然，本来就有严重精神疾病，或是非常孤癖，生活几近与世隔绝的连环杀手也并非没有。造成连环杀人心理的成因众说纷纭，部份连环杀手曾被确认为幼年受虐导致，另外有些科学家经过脑部扫瞄发现部分连环杀手的脑结构有与常人相异之处，提出连续杀人犯可能可以早期筛选出来的假设，引起更大争议。

Art

Collecting art created by convicted serial killers has become a special pastime for some. John Wayne Gacy drew and painted art from prison, much of which he gave away. Some people took Gacy's work just to trash or burn it, especially after discovering that many of his images depicted his own victims. In 2005, serial killer Alfred Gaynor's art was offered on an online auction. One of his more popular works, titled "A Righteous Man's Reward", was a drawing depicting the figure of Jesus.