| Election Name: | 2018 Iowa State Senate election |
| Country: | Iowa |
| Flag Image: | Flag of Iowa (variant).svg |
| Type: | legislative |
| Ongoing: | no |
| Previous Election: | 2016 Iowa Senate election |
| Previous Year: | 2016 |
| Next Election: | 2020 Iowa Senate election |
| Next Year: | 2020 |
| Seats For Election: | 25 out of 50 seats in the Iowa State Senate |
| Majority Seats: | 26 |
| Election Date: | November 6, 2018 |
| Leader1: | Charles Schneider |
| Party1: | Republican Party (United States) |
| Leaders Seat1: | 22nd district |
| Last Election1: | 29 |
| Seats Before1: | 29 |
| Seat Change1: | 3 |
| Seats After1: | 32 |
| Popular Vote1: | 274,664 |
| Percentage1: | 44.09% |
| Leader2: | Janet Petersen |
| Party2: | Democratic Party (United States) |
| Leaders Seat2: | 18th district |
| Last Election2: | 20 |
| Seats Before2: | 20 |
| Seat Change2: | 2 |
| Seats After2: | 18 |
| Popular Vote2: | 348,325 |
| Percentage2: | 55.91% |
| Leader3: | David Johnson |
| Party3: | Independent (United States) |
| Leaders Seat3: | 1st district (retired) |
| Last Election3: | 1[1] |
| Seats Before3: | 1 |
| Seat Change3: | 1 |
| Seats After3: | 0 |
| President of the Senate | |
| Before Election: | Charles Schneider |
| Before Party: | Republican |
| After Election: | Charles Schneider |
| After Party: | Republican |
| Map Size: | 400px |
The 2018 Iowa State Senate elections took place as part of the biennial 2018 United States elections. Iowa voters elected state senators in half of the state senate's districts—the 25 odd-numbered state senate districts. State senators serve four-year terms in the Iowa State Senate, with half of the seats up for election each cycle.
The primary election on June 5, 2018, determined which candidates appeared on the November 6, 2018 general election ballot. Primary election results can be obtained here.[2]
Following the previous 2016 Iowa Senate election, Republicans flipped control of the Iowa state Senate, taking control away from the Democrats.
To reclaim control of the chamber from Republicans, the Democrats needed to net 6 Senate seats.
Republicans expanded their control of the Iowa State Senate following the 2018 general election, increasing their majority from 29 to 32 seats. Democrats saw their numbers dwindle from 20 to 18 seats. The lone Independent member of the IA state Senate was replaced by a Republican as well.
Seats where the margin of victory was under 10%:
| align=center | District 1 • District 3 • District 5 • District 7 • District 9 • District 11 • District 13 • District 15 • District 17 • District 19 • District 21 • District 23 • District 25 • District 27 • District 29 • District 31 • District 33 • District 35 • District 37 • District 39 • District 41 • District 43 • District 45 • District 47 • District 49 |