Robert L. "Bob" McCaslin (April 20, 1926 – March 13, 2011), also known as the Bob McCaslin, Sr., was an American politician of the Republican Party. McCaslin served 30 years, from 1981 to 2011, in the Washington State Senate representing the 4th Legislative District, which includes the areas east of the city of Spokane. Previously, he had served 6 years on the Spokane Valley Fire Commission during the 1970's.