The party won control of West Somerset and Mendip councils and held on to power at Sedgemoor.
Liberal Democrats lost 12 seats at councils across the county, but kept control of South Somerset.
Labour, which has traditionally struggled in the county, gained six more seats.
Taunton Deane Borough Council remains with no one party in overall control - the Conservatives have 28 seats but not a majority.
No party has overall control in Bath and North East Somerset - the Lib Dems and Tories have 29 seats each.
The Tories retained control of North Somerset Council.
The party also held Shepton Mallet in the Somerset County Council by-election, which was held after one Conservative councillor moved away from the area.
John Parham, a Mendip district councillor, was elected as the county councillor for the area.
The new West Somerset Council consists of 19 Conservatives, two Labour and seven independents.
It was previously run by Conservative leader Tim Taylor in coalition with independents.
Mr Taylor said the lack of a controlling group had weakened the council in recent years but that he felt the authority would now be in a better situation to deal with financial challenges.
He said: "I believe that we'll have good leadership, good team work and this will give us strength to negotiate with government to try and get our very challenging finances put right."
Conservatives in Somerset are celebrating winning an extra 15 seats across Somerset in local council elections.