Shediac is a geographic parish in Westmorland County, New Brunswick, Canada.

For governance purposes it is divided between the city of Dieppe, the towns of Cap-Acadie and Shediac, the incorporated rural communities of Beausoleil and Maple Hills, and the Southeast rural district. Beausoleil is a members of the Kent Regional Service Commission, with the rest all belonging to the Southeast Regional Service Commission.

Prior to the 2023 governance reform, the parish was divided between Dieppe, Shediac, the village of Cap-Pelé, the rural community of Beaubassin East, and the local service districts of Grande-Digue, Pointe-du-Chêne, Scoudouc, Scoudouc Road, Shediac Bridge-Shediac River, Shediac Cape, and the parish of Shediac. With minor boundary changes, Grande-Digue and Shediac Bridge-Shediac River are now part of Beausoleil; Pointe-du-Chêne, Scoudouc, Scoudouc Road, and Shediac Cape were annexed by Shediac; Cap-Pelé and Beaubassin East merged to form Cap-Acadie; and the Shediac Parish LSD was divided between Beausoleil and Maple Hills.

The parish's name comes the community of Shediac, itself from a corruption of Mi'kmaq Es-ed-ei'-ik, translated by Rand as "running far back." There was a Fort Shediac mentioned in documents around 1755, on the mainland opposite Shediac Island.

Shediac was erected in 1827 from Dorchester and Sackville Parishes. The eastern boundary was at the mouth of the Kouchibouguac River.

In 1850 the eastern boundary was moved to run through Cap-Pelé.

In 1894 the existing boundaries were declared retroactive to the parish's erection.

In 1904 the boundary with Botsford Parish was clarified.