Twin films are films with the same, or very similar, plot produced or released at the same time by two different film studios. The phenomenon can result from two or more production companies investing in similar scripts around the same time, resulting in a race to distribute the films to audiences. Some attribute twin films to industrial espionage, the movement of staff between studios, or that the same screenplays are sent to several film studios before being accepted. Another possible explanation is if the films deal with topical issues, such as volcanic eruptions, reality television, terrorist attacks or significant anniversaries, resulting in multiple discovery of the concept.
Notes: Not all of these would I classify as Twin Films, but I wanted to stay true to the Wiki page, Also Initially I just listed the 'original' twin movies, I may go back later and insert the additional ones mentioned in the "Further Info" column.