Circle K International (CKI) is an international collegiate service organization that is a service leadership program of Kiwanis International. It promotes service, leadership, and fellowship. It has over 13,000 members.^[3]

Circle K International is a service organization formed to help the community through various service projects. It is part of an umbrella of organizations led by Kiwanis International. Circle K International also aims to build fellowship and create leaders within the membership.

The organization raises funds for various causes. The major initiative is: “Focusing on the Future: Children” which aims to help children of ages six to thirteen. In 2007, Circle K partnered with the U.S. Fund^[4] to help raise $500,000 for UNICEF in efforts to help children around the world who do not have access to clean drinking water. This is called "Saving Lives – The Six Cents Initiative." It got its name from the cost in U.S. funds, to purchase one pack of rehydration salts to purify a day's worth of drinking water. Their service partners include UNICEF, Students Team Up to Fight Hunger (STUFH),^[5] March of Dimes, Better World Books, Junior Chamber International, and the St. Baldrick's Foundation.^[6]

In 2017, Circle K International partnered with UNICEF to adopt the five-year signature project WASH. Circle K International aims to provide education, awareness, and funding to supply clean drinking water and sanitation education to schools and children in Haiti to target Haiti's emergency needs to reach 200,000 people in cholera-affected areas with a complete WASH response package.

"I pledge to uphold the Objects of Circle K International, to foster compassion and goodwill toward others through service and leadership, to develop my abilities and the abilities of all people, and to dedicate myself to the realization of humanity’s potential."

In 1936, the "Circle K House" at Washington State College was established by the Kiwanis Club of Pullman, Washington. Organized as a fraternity, Kappa Iota Phi served men who needed financial aid to attend college. Kiwanians also wanted to provide collegiate students leadership opportunities for their future careers and work service projects to better their communities while having a sense of fellowship. In 1947, Circle K changed from a fraternity to a service organization. That year, the first Circle K club was chartered at Carthage College in Carthage, Illinois. In 1949, two more clubs were added, and by 1955 there were 147 clubs, at which point Circle K received official endorsement from Kiwanis International. Circle K International adopted the Kiwanians beliefs by establishing the three tenets of Service, Leadership, and Fellowship to bring a sense of purpose to the organization.^[7]

The Kiwanis International Board of Trustees accepted a proposal to allow the establishment of Circle K Districts on February 22, 1957. The very first Circle K District to be officially recognized was the Texas-Oklahoma District. The second Circle K District was Kentucky-Tennessee which was closely followed by Michigan. Four more Districts were added in the 1957–58 administrative year: Missouri-Arkansas, California-Nevada-Hawaii, Ohio, and Alabama.

In 1971, delegates at the International Convention voted to allow women into the organization. The move was initially met with resistance by Kiwanis, which must approve all changes to the Circle K governing documents. After nearly two years of debate, the Kiwanis International Board of Trustees approved the change on February 6, 1973 and Circle K became the first co-ed organization in the Kiwanis Family. In 1984, Susan E. McClernon was elected the first female International President of Circle K International.

In 1975, Gregory Faulkner from the New York District was elected to the position of International President. Faulkner was the first African-American International President. Faulkner's election and the admission of female members was symbolic of the new level of maturity and responsibility Circle K International had assumed over 20 years of service, growth and development.

At the International Convention in 1987, the delegates approved the use of the initials CKI as an official name of the organization. That same year, Kiwanis International voted to allow women into Kiwanis clubs. Key Club had gone co-ed in 1977.

As of the end of 2005, membership consisted of over 13,250 college students in 17 nations around the world. Most of the Circle K membership currently resides in North America, in 30 Districts recognized by Kiwanis International. Twenty-seven districts are entirely within the United States, while three districts are international representing Canada and the Caribbean. These three Districts are the Pacific Northwest (made up of Oregon, Idaho, Washington, and the Canadian province of British Columbia and Yukon Territory), Western Canada (Alberta and Manitoba), and Eastern Canada and the Caribbean. Districts-in-Formation exist in Eastern Canada, Central and South America, Australia, and the Pacific Rim.

Circle K International celebrated its 50th anniversary at the 2005 International Convention in Greensboro, North Carolina. The International Convention's theme was, "CKI's 50th Anniversary: 50 Never Looked So Good".

In 2020, due to the COVID-19 pandemic in the United States, the 2019-2020 International Board announced on April 22, 2020 that the upcoming convention in Las Vegas was canceled. The event was rescheduled for July 18, 2020 - July 19, 2020 as the organization's first free virtual conference and had over 955 registered attendees. The International Council convened for a virtual meeting on July 21, 2020 to elect officers for the International Board and to consider amendments to the policy code. In June 2021, due to the continued threat of the pandemic, CKI members were invited to the Kiwanis Education & Leadership Conference in Salt Lake City, Utah instead of holding their own International Convention. Once again, the International Council convened for a meeting to elect officers for the International Board and to consider amendments to the policy code instead of holding the traditional full House of Delegates.

CKI operates on a three-tiered system similar to Kiwanis International and Key Club International. The International Board oversees organizational policy, growth and international expansion. The International Board is elected at the International Convention held in a different city each summer. The CKI Board is composed of an International President, Vice-President, and eight trustees who represent assigned districts. The International Board meets in-person a minimum of four times per year.

A. ^{^} Mr. Creasy and Mr. Alford were president before a charter and separate constitution and by-laws were created for Circle K.