Meon Valley (/ˈmiːɒn/) is a parliamentary constituency^{[n 1]} in Hampshire represented in the House of Commons of the UK Parliament by Flick Drummond, a Conservative, since 2019. It had previously been represented since its 2010 creation by George Hollingbery.^{[n 2]}

Further to the completion of the 2023 Periodic Review of Westminster constituencies, the constituency will be subject to major boundary changes abolishing the seat and dividing it between three.^[2] The bulk of the constituency namely Waterlooville and the surrounding villages will be moved to Fareham and Waterlooville. Horndean will be moved to East Hampshire of-setting losses moved into the new cross-county Surrey seat of Farnham and Bordon. Other western areas will move into Winchester and Hamble Valley.

It is a generally rural constituency, and an affluent safe seat^[3] for the Conservatives. The largest towns in the constituency are Waterlooville and Horndean.

Output areas in the area in 2001 displayed higher than average incomes overall compared to the national average.^[4] In the 2011 census, incidence of home ownership and incidence of semi-detached and detached properties all exceeded the national average and were some of the highest figures for the region.^[5]

This seat has been formed by the Boundary Commission for England as an extra constituency in Hampshire, with electoral wards from East Hampshire, Havant and Winchester districts.

• From East Hampshire - the wards of Clanfield and Finchdean, Horndean Catherington and Lovedean, Horndean Downs, Horndean Hazleton and Blendworth, Horndean Kings, Horndean Murray and Rowlands Castle
• From Havant - the wards of Cowplain, Hart Plain and Waterloo
• From Winchester - the wards of Bishops Waltham, Boarhunt and Southwick, Cheriton and Bishops Sutton, Denmead, Droxford, Soberton and Hambledon, Owslebury and Curdridge, Shedfield, Swanmore and Newtown, Upper Meon Valley, Whiteley and Wickham

The wards included are largely from parts of the former Winchester and East Hampshire parliamentary seats with some 600 voters from the Havant constituency which is otherwise unchanged.

The 2023 Periodic Review of Westminster constituencies proposed to break up the Meon Valley constituency, with the parliamentary constituencies of Winchester, Fareham and Waterlooville and East Hampshire taking over areas of the constituency. The plans went through Parliament by July 2023.^[6]

When created, the notional result was based on ward data from the previous seats' general election results. The new constituency takes in territory from the then Liberal Democrat-held Winchester and Conservative-held East Hampshire with uncertain swing between the two parties . Estimates were that the Conservative majority if the seat had existed in 2005 would have been around 2,000 votes. At the 2010 election however, the seat saw one of the largest Liberal Democrat to Conservative swings (9.4%), and the Conservative candidate George Hollingbery was elected with a majority of over 12,000. A similar swing was recorded in the neighbouring Winchester seat, which was a Conservative gain. It would now take a swing of almost 12% for any party to gain Meon Valley and more than 24% swing for Labour.

Following the 2015 general election it is one of the safest Conservative seats in the country.

Further to the completion of the 2023 Periodic Review of Westminster constituencies, the seat will be abolished for the next general election, with its contents distributed four ways:^[2]

• The town of Waterlooville, together with the villages of Denmead, Southwick and Wickham, included in the new constituency of Fareham and Waterlooville
• Horndean transferred to East Hampshire
• The City of Winchester ward of Whiteley and Shedfield included in the new constituency of Hamble Valley
• Remaining, largely rural areas, including the town of Bishop's Waltham, transferred to Winchester

• List of parliamentary constituencies in Hampshire