Sir Frederic Truby King, generally known as Truby King, was a New Zealand health reformer and Director of Child Welfare. He is best known as the founder of the Plunket Society.

The Royal New Zealand Plunket Trust provides a range of free services aimed at improving the development, health and wellbeing of children under the age of five within New Zealand, where it is commonly known simply as Plunket. Its mission is "to ensure that New Zealand children are among the healthiest in the world". Much of Plunket's work is organised by volunteers.