Line 18

Line 18 may refer to:

China

 * Line 18 (Chengdu Metro)
 * Line 18 (Chongqing Rail Transit) (under construction)
 * Line 18 (Guangzhou Metro)
 * Line 18 (Shanghai Metro)

Other countries

 * Line 18 (São Paulo Metro), Brazil (cancelled)
 * Line 18 (Stockholm Metro), a Green line, Sweden
 * Line 18 (Zürich), or Forch railway, Switzerland
 * Paris Métro Line 18, France (planned)
 * Line 18, serving the Sinsen Line of the Oslo Tramway, Norway