Yellow flag
# Yellow flag

Yellow flag may refer to:

* Iris pseudacorus, an aquatic flowering plant
* A flag of a yellow colour:
   * Yellow flag (contagion), historically displayed on ships to indicate the presence of disease or quarantine (obsolete); also used in some cities to mark a recent death in a neighborhood, regardless of cause
   * Racing flags, used in motor sports to indicate hazardous conditions
   * Penalty flag, used in various sports including American football
   * Yellow Flag Line, transport on the Chao Phraya River, with service indicated by the flag color
   * Yellow Dragon Flag, the flag of the Qing dynasty
* The Yellow Flag, 1937 German drama film
* Yellow Banners of the Eight Banner system
   * Plain Yellow Banner
   * Bordered Yellow Banner
