Meeney joined Horsham in May just after the 2017/18 season had finished.
The former Worthing joint-manager made the switch from National League South Eastbourne Borough to take up the head coach role.
Before that he had a long-running relationship and role at Worthing. His last was being appointed joint boss with Gary Elphick in 2015 where they guided the Rebels to promotion through, the then, Ryman South play-offs, in their first season in charge.
Meeney announced the news on twitter. He said: "I'd like to place on record, I am no longer involved with @HorshamFC due to increasing coaching commitments elsewhere - Would like to thank all involved during my time, & wish the management team & players the very best of luck. Really believe you are on to something good!"
At the time of the appointment, the former Brighton and Chelsea coach explained: “After I left Worthing as manager I was in a bit of limbo really of what my next move would be as it was a bit of a premature departure from Worthing. I had known Jamie Howell for a long time and had the chance to go down to Eastbourne Borough as first team coach.
“Horsham then made an approach to Eastbourne. I have known Dom for many, many years both on and off the pitch. He asked if I could come in and be the man structuring the football model along with the exciting things that are happening at Horsham."