Double line may refer to:

• Double-track railway, a type of railway with two tracks, usually involving running a track in each direction
  • Double line automatic signalling, a form of railway signalling used on the majority of double track sections in New Zealand
• Double-lined mackerel, Grammatorcynus bilineatus, a species of Spanish mackerel
• Double-lined spectroscopic binary, a type of binary star: see Binary star#Spectroscopic binaries
• Mythimna turca , common name the double line, a moth of the family Noctuidae
• In algebraic geometry, a certain family of conics

This disambiguation page lists articles associated with the title Double line.
If an internal link led you here, you may wish to change the link to point directly to the intended article.