Ilsanseo District () is a district in Goyang, Gyeonggi-do, South Korea. Ilsan-gu was divided into Ilsandong District and Ilsanseo District on May 16, 2005.
It is a district located in the western part of Goyang-si, Gyeonggi-do. It has an area of 42.15 km<sup>2</sup> and is divided into Ilsandong-gu to the east and Ilsanseo-gu to the west, centered on Gobong-ro, which connects Jungsan and Hosu Park. It borders Paju-si to the north and Gimpo-si to the west across the Han River.
Ilsanseo District is divided into 9 dong (ëÂÂ, "neighborhoods"):
Ilsanseo District has 46 schools including: 22 elementary schools, 12 middle schools, 9 high schools, and 2 special schools.
Hugok () is notable for their hagwons (ÃÂÂìÂÂ, "cram school"), and many hagwons are present in the region.
To improve the living environment of ordinary citizens, 1,800 private rental housing units are scheduled to be built in Deok-i-dong.