The Sir Thomas & Lady Duncan Trust is a charitable trust based in the Rangitikei, New Zealand.

The Trust was established in 1946 by Sir Thomas and Lady Duncan in response to the polio epidemic in New Zealand at that time.  Sir Thomas and Lady Duncan funded the investigation of treatment for polio and established a polio hospital in Silverstream Wellington (which was later relocated to Durie Hill, Wanganui).  The hospital was funded by “Otiwhiti”, a sheep station located at Otairi, Hunterville in the Rangitikei which was gifted to the Trust by Sir Thomas and Lady Duncan.

The Trust continues to support sufferers of polio but it also supports those with other neuro-muscular disorders, particularly children, and funds research into causes, cure and prevention of such disorders.

A board of trustees, the majority of whom are direct descendants of Sir Thomas and Lady Duncan, administers the Trust.