St Albans City’s boss leaves the Clarence Park dug-out after six years at the helm.
Earlier, Gloucester City parted company with Lee Mansell moments before Brackley Town announced long-serving manager Kevin Wilkin was being replaced by Roger Johnson.
National League South St Albans decided it was time for a change of direction following Tuesday’s 1-0 defeat to Braintree Town.
The Saints hit 15th but he won’t be saying goodbye totally.
He remains in his position as commercial manager, and will support the new boss when an appointment is made.
David Noble will take training until Allinson’s successor is announced. The Hertfordshire club host Chippenham Town on Saturday.
A St Albans statement read: “Following a meeting between the owners and Ian Allinson, the club can confirm that Ian has agreed to step down as first-team manager, by mutual consent, with immediate effect.
“The club would like to extend it’s thanks to Ian for his hard work and dedication over the last 6 years and will always cherish the memories from this period, including last season’s FA Cup first-round victory, a game televised across the nation and beyond and a moment which will forever be remembered in the club’s history.
“Although Ian will not be involved with the footballing side of the club, he will continue his non-football role as commercial manager.
“The club will now look to embark on the recruitment of a Head Coach for the first team and, for the time being, David Noble has agreed to act as Interim Head Coach, supported by the club’s backroom coaching and medical team.”