LTR or ltr may refer to:
== Science and technology ==
Litre (incorrectly abbreviated ltr), a metric unit of volume
Load task register, a computing instruction
Logic Trunked Radio, a computer-controlled radio system
Long terminal repeat, a DNA sequence found in retroviruses and retrotransposons
== Other uses ==
Left to right, a group of writing systems
Letter (paper size)
Model 700P Light Tactical Rifle, a rifle manufactured by Remington Arms
London Turkish Radio
Long-term relationship
== See also ==
"Left to Right", a short story by Isaac Asimov...