| Election Name: | 1984 Delaware gubernatorial election |
| Country: | Delaware |
| Type: | presidential |
| Ongoing: | Yes |
| Previous Election: | 1980 Delaware gubernatorial election |
| Previous Year: | 1980 |
| Next Election: | 1988 Delaware gubernatorial election |
| Next Year: | 1988 |
| Election Date: | November 6, 1984 |
| Image1: | File:Mike Castle 1982.jpg |
| Nominee1: | Mike Castle |
| Party1: | Republican Party (United States) |
| Popular Vote1: | 135,250 |
| Percentage1: | 55.53% |
| Nominee2: | William T. Quillen |
| Party2: | Democratic Party (United States) |
| Popular Vote2: | 108,315 |
| Percentage2: | 44.47% |
| Governor | |
| Before Election: | Pierre S. duPont IV |
| Before Party: | Republican Party (United States) |
| After Election: | Mike Castle |
| After Party: | Republican Party (United States) |
The 1984 Delaware gubernatorial election took place on November 6, 1984. Incumbent Republican governor Pierre S. duPont IV was barred from seeking a third term in office. Lieutenant Governor Mike Castle was elected to succeed him, defeating State Supreme Court Justice William T. Quillen. This was the last time that a gubernatorial nominee and a lieutenant gubernatorial nominee of different political parties were elected governor and lieutenant governor respectively in Delaware.