Essex South West was a constituency of the European Parliament located in the United Kingdom, electing one Member of the European Parliament by the first-past-the-post electoral system.

On its creation in 1979, it consisted of the parliamentary constituencies of Basildon, Brentwood and Ongar, Chelmsford, Epping Forest, Harlow and Thurrock.

[1] After the 1984 boundary changes based on the new UK parliamentary constituencies created in 1983, it consisted of Basildon, Billericay, Brentwood and Ongar, Castle Point, Chelmsford, Epping Forest, Harlow and Thurrock.

Brentwood and Ongar, Chelmsford, Epping Forest and Harlow became part of Essex West and Hertfordshire East.

Basildon, Billericay, Castle Point and Thurrock were now part of the new constituency of Essex South.