The Halton Instructional Assistants Association was created in May of 1984 by a group of individuals employed by the Halton Board of Education as Instructional Assistants. The purpose of the informal Association, at the time of its creation, was to obtain improvements in the terms and conditions of their employment, to protect members from arbitrary or unjust treatment in respect to their employment and generally to advance the economic and social well-being of its members.

In December of 1995, the membership of the Association voted to become a certified Association.Certification was granted on December 11th, 1995 by the Ontario Labor Relations Board. After seventeen months of negotiations, the first Collective Agreement between the then Halton Board of Education and the Halton Instructional Assistants Association was signed on September 23rd, 1997.

Currently the Association has an Executive Committee of six members, with meetings held every second month. Three general meetings of the membership are held during the school year, with the Annual General Meeting in September of each year.

In December of 1997, the Association moved into its first office, at 3425 Harvester Road in Burlington.

In May of 2001, the Association joined the Coalition of Educational Assistants of Ontario (CEAO).

Effective September 4th, 2001, the name of the Association was changed to Halton District Educational Assistants Association, with members now being refered to as Educational Assistants.