Indium trihydride complexes were unknown prior to 1998. This article focuses on the development of this field over the last 4 years. Emphasis is placed on strategies employed to stabilise such complexes, their structure, properties and use in inorganic and organic synthesis. Throughout, comparisons are drawn with the chemistries of related lighter group 13 metal trihydride complexes. A number of similarities and differences have been observed in these comparisons which have been rationalised in terms of the properties of the group 13 elements involved.