In the Canadian Forces, lieutenant-colonel (LCol, French: links=no|lieutenant-colonel or French: lcol) is a rank for officers who wear army or air force uniform, equal to commander for officers who wear navy uniform. Lieutenant-colonel is the second-highest rank of senior officer. A lieutenant-colonel is senior to a major or lieutenant-commander, and junior to a colonel or naval captain.
The rank insignia for a lieutenant-colonel on air force uniforms is three 1-cm stripes of braid, worn on the cuffs of the service-dress jacket, and on slip-ons on other uniforms. On army uniforms, the rank insignia is one pip and a crown.
Lieutenant-colonels are addressed by rank and name and thereafter by subordinates as "Sir" or "Ma'am".
In the Canadian Army, lieutenant-colonels are often employed as commanding officers of battalion-sized groups, such as infantry battalions, armoured regiments, artillery field regiments, engineer field regiments, signal regiments, field ambulances and service battalions.
In the Royal Canadian Air Force, lieutenant-colonels are often the commanding officer of flying or ground squadrons.
Before unification of the Canadian Forces in 1968, rank structure and insignia followed the British pattern.