| Election Name: | 1990 California State Senate election |
| Country: | California |
| Type: | legislative |
| Ongoing: | no |
| Previous Election: | 1988 California State Senate election |
| Previous Year: | 1988 |
| Next Election: | 1992 California State Senate election |
| Next Year: | 1992 |
| Seats For Election: | 20 seats from even-numbered districts in the California State Senate |
| Majority Seats: | 21 |
| Image1: | David Roberti, 1971.jpg |
| Leader1: | David Roberti |
| Party1: | California Democratic Party |
| Leaders Seat1: | 23rd–Los Angeles |
| Seats Before1: | 25 |
| Seats After1: | 26 |
| Seat Change1: | 1 |
| Popular Vote1: | 1,598,096 |
| Percentage1: | 48.09% |
| Leader2: | Kenneth L. Maddy |
| Party2: | California Republican Party |
| Leaders Seat2: | 14th–Fresno |
| Seats Before2: | 14 |
| Seats After2: | 13 |
| Seat Change2: | 1 |
| Popular Vote2: | 1,426,355 |
| Percentage2: | 42.92% |
| Map Size: | 300px |
| President pro tempore | |
| Posttitle: | President pro tempore-designate |
| Before Election: | David Roberti |
| Before Party: | California Democratic Party |
| After Election: | David Roberti |
| After Party: | California Democratic Party |
The 1990 California State Senate elections were held on November 6, 1990. Senate seats of even-numbered districts were up for election. Senate terms are staggered so that half the membership is elected every two years. Senators serve four-year terms and are limited to two terms. The Democratic party won 15 seats, gaining a seat from the Republicans. The Republicans won 4 seats, and Independent Quentin L. Kopp was reelected.[1]
| California State Senate elections, 1990 | ||||||||||
|---|---|---|---|---|---|---|---|---|---|---|
| Party | Votes | Percentage | Not up | Incumbents | Open | Before | After | +/– | ||
| Democratic | 1,598,096 | 48.09% | 5 | 14 | 0 | 19 | 20 | +1 | ||
| Republican | 1,426,355 | 42.92% | 2 | 5 | 0 | 7 | 6 | -1 | ||
| Independent | 116,885 | 3.52% | 0 | 1 | 0 | 1 | 1 | 0 | ||
| Libertarian | 98,517 | 2.96% | 0 | 0 | 0 | 0 | 0 | 0 | ||
| Peace and Freedom | 83,514 | 2.51% | 0 | 0 | 0 | 0 | 0 | 0 | ||
| Totals | 3,323,317 | 100.00% | 7 | 20 | 0 | 27 | 27 | — | ||