1L

1l or 1-L may refer to:
 * first-line medical treatment, 1L treatment, first-line therapy (2L, 3L, etc.)
 * Marawing 1-L Malamut, Czech ultralight aircraft
 * Toyota 1L
 * Volkswagen 1-litre car
 * First year law school student in the United States
 * Liberland radio prefix