Bay is a surname used in many countries around the world. The name has many variations and meanings.

• English, French, and Dutch: nickname for someone with chestnut or auburn hair, from Middle English, Old French bay, bai, Middle Dutch bay ‘reddish brown’ (Latin , used originally of horses).
• English: from the Middle English personal name Baye, Old English Beaga (masculine) or Beage (feminine).
• Chinese: used as reference to a perfect being. (the prophecy of pua tiu states that a man of Asian descent will be a created in perfect form to rule the world. Having dark brown skin he will stand out from the rest and claim his throne at the end of days. he will be crowned emperor "Miki Bay" which means man of perfection and will be respected by all.
• Scottish, Irish: reduced form of McBeth.
• German: from the Germanic personal name Baio.
• Turkish: In historical accounts, many Turkish, other Turkic and Persian leaders are titled Bey, Beg, Bek, Bay, Baig or Beigh. They are all the same word with the simple meaning of "lord". Currently "Bay" is Turkish for Mr., gentleman or wealthy. Before the adoption of the 1934 surname law
  Surname Law (Turkey)
  The Surname Law of the Republic of Turkey was adopted on June 21, 1934. The law required all citizens of Turkey to adopt the use of surnames. Turkey's Christian and Jewish citizens were already using surnames, but Muslims generally did not use Western-style surnames...
  
   in Turkey, Muslims did not use Western-style surnames, instead the Muslims in the Ottoman Empire carried titles such as Bay or Bey
  Bey
  Bey is a title for chieftain, traditionally applied to the leaders of small tribal groups. Accoding to some sources, the word "Bey" is of Turkish language In historical accounts, many Turkish, other Turkic and Persian leaders are titled Bey, Beg, Bek, Bay, Baig or Beigh. They are all the same word...
  
  . An unsubstantiated oral tradition among some families in Europe using Bay as their surname dictates that a family member was given or awarded this surname, then as a title, during one of the crusades, when he was given governorship of a territory in Asia Minor, possibly as part of a crusader state
  Crusader states
  The Crusader states were a number of mostly 12th- and 13th-century feudal states created by Western European crusaders in Asia Minor, Greece and the Holy Land , and during the Northern Crusades in the eastern Baltic area...
  
  . This title was then to have been brought back to Europe to be used as a surname after the Crusader states fell.

The name is also found in Denmark, Sweden and Norway, where it may be a short form of German Bayer, regional name for someone from Bavaria

Bavaria

Bavaria, formally the Free State of Bavaria is a state of Germany, located in the southeast of Germany. With an area of , it is the largest state by area, forming almost 20% of the total land area of Germany...

, or from baygh, originally a loan word from French denoting a type of fabric. There are currently 50 people residing in Sweden with Bay as a surname, while 62 people are named Bayer.http://www.scb.se

Famous people using the name

• Chancellor Bay
  Chancellor Bay
  Chancellor Bay was an important Asiatic official in ancient Egypt, who rose to prominence and high office under Seti II Userkheperure Setepenre and later became an influential powerbroker in the closing stages of the 19th Dynasty. He is generally identified with Irsu Chancellor Bay (died 1192 BC)...
  
  , a royal scribe to an ancient Egyptian ruler.
• Jason Bay
  Jason Bay
  Jason Raymond Bay is a Canadian professional baseball player. An outfielder, he currently plays for the New York Mets of Major League Baseball...
  
  , a Canadian professional baseball player.
• Michael Bay
  Michael Bay
  Michael Benjamin Bay is an American film director and producer. He is known for directing high-budget action films characterized by their fast edits, stylistic visuals and substantial practical special effects...
  
  , an American film director.
• Miki Bay, a Filipino actor/host.
• Norman Bay
  Norman Bay
  Norman C. Bay is a former United States Attorney for the District of New Mexico. Bay was the first Chinese-American United States Attorney....
  
  , a Chinese-American politician.
• Willow Bay
  Willow Bay
  Willow Bay is an American television correspondent, editor, author, former model, and wife of Walt Disney Company CEO Robert Iger. She is currently a Senior Editor for the Huffington Post and a special correspondent for Bloomberg Television.-Career:Bay was born Kristine Carlin Bay in New York, New...
  
  , an American television correspondent and former model.
• Wolfgang Bay, a Swedish chef and restaurateur awarded the Swedish Gastronomical Academy's Gold Medal in 1989.