Knight Commander is the second most senior grade of seven British

United Kingdom

The United Kingdom of Great Britain and Northern IrelandIn the United Kingdom and Dependencies, other languages have been officially recognised as legitimate autochthonous languages under the European Charter for Regional or Minority Languages...

 orders of chivalry, three of which are dormant (and one of them continues as a German house order). The rank entails admission into knighthood, allowing the recipient to use the title 'Sir' (male) or 'Dame' (female) before his or her name. In the British system of precedence

Commonwealth Realms orders and decorations

This article concerns the orders and decorations of the Commonwealth realms awarded by the sovereign in right of each nation.Awards are listed by order of wear.-Antigua and Barbuda:* The Most Exalted Order of the National Hero...

, Knights (and Dames) Commander rank after the Order of the Companions of Honour

Order of the Companions of Honour

The Order of the Companions of Honour is an order of the Commonwealth realms. It was founded by King George V in June 1917, as a reward for outstanding achievements in the arts, literature, music, science, politics, industry or religion....

 (although Companions of Honour obtain no knighthood or other status) and before Knights Bachelor

Knight Bachelor

The rank of Knight Bachelor is a part of the British honours system. It is the most basic rank of a man who has been knighted by the monarch but not as a member of one of the organised Orders of Chivalry...

.

The Orders that award the rank of Knight Commander, and related post-nominal letters

Post-nominal letters

Post-nominal letters, also called post-nominal initials, post-nominal titles or designatory letters, are letters placed after the name of a person to indicate that the individual holds a position, educational degree, accreditation, office, or honour. An individual may use several different sets of...

, are (dormant orders in italics):

• Order of the Bath
  Order of the Bath
  The Most Honourable Order of the Bath is a British order of chivalry founded by George I on 18 May 1725. The name derives from the elaborate mediæval ceremony for creating a knight, which involved bathing as one of its elements. The knights so created were known as Knights of the Bath...
  
   (KCB / DCB)
• Order of the Star of India
  Order of the Star of India
  The Most Exalted Order of the Star of India is an order of chivalry founded by Queen Victoria in 1861. The Order includes members of three classes:# Knight Grand Commander # Knight Commander # Companion...
  
   (KCSI)
• Order of St Michael and St George
  Order of St Michael and St George
  The Most Distinguished Order of Saint Michael and Saint George is an order of chivalry founded on 28 April 1818 by George, Prince Regent, later George IV of the United Kingdom, while he was acting as Prince Regent for his father, George III....
  
   (KCMG / DCMG)
• Royal Guelphic Order
  Royal Guelphic Order
  The Royal Guelphic Order, sometimes also referred to as the Hanoverian Guelphic Order, is a Hanoverian order of chivalry instituted on 28 April 1815 by the Prince Regent . It has not been conferred by the British Crown since the death of King William IV in 1837, when the personal union of the...
  
   (KCH)
• Order of the Indian Empire
  Order of the Indian Empire
  The Most Eminent Order of the Indian Empire is an order of chivalry founded by Queen Victoria in 1878. The Order includes members of three classes:#Knight Grand Commander #Knight Commander #Companion...
  
   (KCIE)
• Royal Victorian Order
  Royal Victorian Order
  The Royal Victorian Order is a dynastic order of knighthood and a house order of chivalry recognising distinguished personal service to the order's Sovereign, the reigning monarch of the Commonwealth realms, any members of her family, or any of her viceroys...
  
   (KCVO / DCVO)
• Order of the British Empire
  Order of the British Empire
  The Most Excellent Order of the British Empire is an order of chivalry established on 4 June 1917 by George V of the United Kingdom. The Order comprises five classes in civil and military divisions...
  
   (KBE /DBE)

Knights (and Dames) Commander rank behind the most senior rank in each order, that of Knights Grand Cross

Knight Grand Cross

Knight Grand Cross is the most senior grade of seven British orders of chivalry, three of which are obsolete. The rank entails admission into knighthood, allowing the recipient to use the title 'Sir' or 'Dame' before his or her name...

. The third most senior rank in each order is a Companion (CB, CSI, CMG, CIE), Knight (KH) or Commander (CVO, CBE). Insignia

Insignia

Insignia or insigne pl -nia or -nias : a symbol or token of personal power, status or office, or of an official body of government or jurisdiction...

 include a breast star, a badge, and a ribbon.

It is also a grade in the orders of other countries, such as the Order of St. Gregory the Great

Order of St. Gregory the Great

The Pontifical Equestrian Order of St. Gregory the Great , was established on September 1, 1831, by Pope Gregory XVI, seven months after his election.It is one of the five orders of knighthood of the Holy See...

. The Italian equivalent is Commendatore

Commendatore

Literally Commander, the official title of Commendatore is awarded by decree of the President of Italy to individuals who are given this honour in the Italian Order of Merit known as the Ordine al Merito della Repubblica and other orders of knighthood...

.