| Lilja Guðmundsdóttir | |
| Nationality: | Icelandic |
| Sport: | Middle-distance running |
| Event: | 800 metres |
| Birth Date: | 3 January 1955 |
Lilja Guðmundsdóttir (born 3 January 1955) is an Icelandic middle-distance runner. She competed in the women's 800 metres at the 1976 Summer Olympics.[1]