Jeacock is the second young Blues goalkeeper to be loaned out this week, following on from Michael Luyambula who joined league Two Crawley Town for the season.BCFC
Jeacock made 10 appearances for Blues Under-23s last season and 13 for the Under-18s age group.
The Birmingham-born stopper joined Blues back in 2009 and was only converted to a goalkeeper at the age of 14, having previously played as a defender.
The highly rated youngster, who turned 18 in May, was recently included in an England age group training camp
Earlier this summer, he signed his first professional contract with the Club, which runs until 2022.
Gloucester, who are in the National League North, currently play their home games at the 3,000 capacity Jubilee Stadium in Evesham.
The Tigers kick off their 2019/20 league campaign on 3 August with a long trip to Blyth Spartans.
Scott Bevan, Blues Under-23s Goalkeeper Coach, commented: "This loan is a great opportunity for Zach and is the next step in his journey to try and become Birmingham City’s number one.
"He has shown great development over the last 18 months with our Under-18 and Under-23 teams and proven that he can handle, plus excel, in Academy football.
"The chance to now get him out at Conference North level and playing competitive men’s football to a team the size of Gloucester City was too good to turn down and we feel it will help further aid his evolution as a goalkeeper.
"We thank Gloucester manager Mike Cook for giving Zach the chance to show what he can do and we wish them both well for the upcoming season."
Jeacock is the second young Blues goalkeeper to be loaned out this week, following on from Michael Luyambula who joined league Two Crawley Town for the season.