Illighausen is a village and former municipality in the canton of Thurgau, Switzerland.
It was first recorded in the year 1176 as Illinchusen.
The municipality had 284 inhabitants in 1850, which increased to 295 in 1900 but then decreased to 275 in 1950 and 241 in 1990.
In 1998 the municipality was merged with the neighboring municipality Oberhofen bei Kreuzlingen, to form a new and larger municipality called Lengwil.