New Zealand Rugby Chief Executive Steve Tew acknowledged Cooper's commitment and contribution to the Chiefs and NZ Rugby.
"Coops is a remarkable individual with great presence and mana. We know Coops to have a special talent in communicating with young men and working to bring the best out of those in his charge, and to help grow outstanding individuals on and off the field.
"We appreciate that he will have some decisions to make and while he will have choices in front of him, we hope his special abilities won't be lost to New Zealand rugby.
"Next year is a post-World Cup year when there is a lot of player movement within Investec Super Rugby and clubs are beginning the next four-year cycle. Taking that into consideration, both Colin and the club have spoken at length over several weeks and agree that the time is right for a new coach to take the Chiefs into 2020 and beyond.
"Being an ultimate professional and team man, Colin's early decision was not made lightly by either him or the club, but it has allowed us some space to recruit and plan for a smooth and successful transition."
Under Cooper, the Chiefs reached the quarterfinals of the 2018 and 2019 Super Rugby competition.
Cooper said he was proud to have been part of the Chiefs and leading a "great group of young men".
"I believe the team and the club are bigger than the individual and the club comes first. With next year the start of a new World Cup cycle, I believe it is the right time to step aside. There is a good crew of players and staff here who are committed to carrying the club forward," Cooper said.
"Developing young players and coaches for the future of New Zealand rugby is something I'm very passionate about, and I'm proud and grateful to have been a part of that with the Chiefs.
"The Chiefs and the club are well supported by fans and sponsors, and I would like to thank them for making me feel welcome and at home in Hamilton.
"For now, my focus is to complete our season review, and then my priority is to spend time with my whanau, and moko who are continuing to grow."
Cooper has been coaching rugby professionally for more than 20 years. He took on the role of Chiefs head coach after eight successful seasons leading the Taranaki Mitre 10 Cup team, during which time he also coached the Māori All Blacks for five years. Previously he was head coach of the Hurricanes for eight years.
Cooper said he would now take a break to consider his future.
"The role of the head coach has evolved so much over the past five or six years. My passion is 'hands-on' on-the-field coaching, but with bigger playing numbers and more staff involved these days, I am getting taken further and further away from my passion. So I will take some time out with my family and discuss our future."
Collins thanked Cooper for his contribution to rugby and the community within the Chiefs' region.
"Coops is a person of huge mana – he is a man of integrity. He has done a fantastic job over a number of years developing players, coaches and other support staff. He has done a great job of identifying talent and getting that talent into the Chiefs system. The Chiefs Rugby Club wish Colin and his family all the best for their future endeavours."
Chiefs co-captain Sam Cane said Cooper has been a great mentor.
"Coops has a huge amount of mana and respect from the team. A number of us have played under his leadership for several years, some for even longer. He has been a great coach and mentor during his time at the Chiefs. His knowledge and experience has been hugely beneficial, and he's been instrumental in developing some of our talented younger guys. He will be missed, but we wish Coops all the best in his next venture."
