HMS Princess Royal was the second of two Lion-class battlecruisers built for the Royal Navy before the First World War. Designed in response to the Moltke-class battlecruisers of the Imperial German Navy, the ships significantly improved on the speed, armament, and armour of the preceding Indefatigable class. The ship was named after Louise, The Princess Royal, a title occasionally granted to the Monarch's eldest daughter.

The Lion class were a pair of battlecruisers built for the Royal Navy before World War I. Nicknamed the "Splendid Cats", the ships were a significant improvement over their predecessors of the Indefatigable class in speed, armament and armour. These improvements were in response to the German battlecruisers of the Moltke class, which were in turn larger and more powerful than the first British battlecruisers of the Invincible class.