Maynard was in charge of the county between 2008 and 2010 before returning in 2017 as a batting consultant. He began his second stint as head coach in 2019
Glamorgan have opted to split the head coaching responsibilities at the county, with Matthew Maynard taking the reins in red-ball cricket.
The club will recruit a limited overs head coach in near future.
Maynard, who has signed a two-year contract extension with the club, first served as head coach between 2008 and 2010. He then returned as a batting consultant in 2017 before taking over as head coach for the second time in 2019.
As interim head coach in 2019, he led Glamorgan to fourth place in Division Two while this season, the county missed out on promotion to Division One by just nine points.
Commenting on his new role, Maynard said: "I'm delighted to be able to carry on the work we've put in over the last three years in the four-day game.
Glamorgan will recruit a limited overs head coach [Shaun Botterill/Getty Images]
"Although I enjoy coaching the white-ball sides, I fully respect the decision made by the club to split the head coach duties, and as always will do my best for Glamorgan Cricket.
"Taking charge of just the red-ball team will allow me to concentrate my efforts and hopefully we can go one better next year and secure promotion to Division One.
"We have a talented squad who are a pleasure to work with and I can't wait to get started with them again over the winter.
"The dynamic with a new head coach will be something different and hopefully we get the right character in to fit in with the culture and environment we've created over the past few years, but it's very exciting and I'm looking forward to discussing strategy and tactics, and working with them so we can get the best results over all three formats for the club."
Director of cricket, Mark Wallace, added: "Matt has done an excellent job in red-ball cricket where we've seen a big improvement in our performances over the last couple of years and it's good that we can retain his experience and expertise to take us forward in that format
"It's a very long season with a lot of cricket and we believe that splitting the role will allow for the coaches to remain fresh and focus on the differing requirements of the various formats of the game."