Andrew E. Dinniman (born October 10, 1944) is an American politician who served as a Democratic member of the Pennsylvania State Senate for the 19th District from June 2006 until 2020.

After the death of Republican Senator Robert "Bob" Thompson in 2006, Dinniman sought and attained his party's nomination to run in the ensuing special election.

In what was considered a political surprise, Dinniman won with 56% of the vote, becoming the first Democrat elected to represent Chester County in the state Senate since the 1920s.

At the time of his retirement, Dinniman sat on five committees: Education; Communications and Technology; Agriculture and Rural Affairs; Environmental Resources and Energy; and State Government.

[11] He endorsed Manan Trivedi, a doctor from Reading, who went on to win the Democratic primary, but lost the fall general election to Gerlach.