The 1918 Iowa State Senate elections took place as part of the biennial 1918 United States elections. Iowa voters elected state senators in 23 of the state senate's 50 districts. State senators serve four-year terms in the Iowa State Senate. A statewide map of the 50 state Senate districts in the 1918 elections is provided by the Iowa General Assembly here. The primary election on June 3, 1918 determined which candidates appeared on the November 5, 1918 general election ballot. Following the previous election, Republicans had control of the Iowa Senate with 40 seats to Democrats' 10 seats.