In the Canadian Forces, lieutenant-colonel (LCol, French: lieutenant-colonel or 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.

• Army uniform variations
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  Dress uniform tunic
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  Uniform shirts
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  Olive green uniforms (old insignia)
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  CADPAT uniform (old insignia)
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  Arid-region CADPAT uniform (old insignia)

• Air force uniform variations
• 
  Dress uniform tunic
• 
  Uniform shirts (old insignia)
• 
  CADPAT uniform