| Election Name: | 2005 Hertfordshire County Council election |
| Country: | Hertfordshire |
| Type: | Parliamentary |
| Ongoing: | no |
| Previous Election: | 2001 Hertfordshire County Council election |
| Previous Year: | 2001 |
| Next Election: | 2009 Hertfordshire County Council election |
| Next Year: | 2009 |
| Seats For Election: | All 77 seats to Hertfordshire County Council |
| Majority Seats: | 39 |
| Election Date: | 5 May 2005 |
| Party1: | Conservative Party (UK) |
| Seats1: | 46 |
| Seat Change1: | 6 |
| Popular Vote1: | 215,247 |
| Percentage1: | 42.5% |
| Swing1: | 4.6% |
| Party2: | Labour Party (UK) |
| Seats2: | 16 |
| Seat Change2: | 11 |
| Popular Vote2: | 132,168 |
| Percentage2: | 26.1% |
| Swing2: | 7.7% |
| Party3: | Liberal Democrats (UK) |
| Seats3: | 14 |
| Seat Change3: | 4 |
| Popular Vote3: | 132,926 |
| Percentage3: | 26.3% |
| Swing3: | 2.6% |
| Council control | |
| Posttitle: | Council control after election |
| Before Election: | Conservative |
| After Election: | Conservative |
Hertfordshire County Council elections were held on 5 May 2005, with all 77 seats contested. The Conservative Party reinforced its hold on County Hall and only the loss of 2 seats in Dacorum Borough detracted from a strong showing across the County. It maintained a stranglehold on the Eastern part of the County, winning all of the seats in Broxbourne District and East Herts District.
The Liberal Democrats made a strong showing in Watford and St Albans District and made gains in Tring Division (Dacorum) and Chells Division (Stevenage) from Conservatives and Labour respectively.
The Labour Party were the main losers on the day, with a net loss of 11 seats and being beaten into third place in the popular vote. The Conservative Party and the Liberal Democrat Party were the main benefactors from Labour's poor performance, gaining 6 seats and 4 seats respectively. The Greens gained a single seat in Watford District (Callowland Leggatts), again at Labour's expense. Labour would find little consolation from this election suffering significant losses throughout the central and western parts of the County. Stevenage Borough remained as the only Labour stronghold and even here the Liberal Democrats won Chells Division.