Centennial High School is a public high school located in Roswell, Georgia, United States. It opened in 1997. The school was named in honor of the 1996 Olympic games held in Atlanta a year before the school's opening, which marked the centennial anniversary of the modern games.

The school's mascot is the Knight.

Centennial High School is housed in a 271,200-square-foot (25,200 m) educational facility sitting on 55 acres (220,000 m) within the city limits of Roswell. Over the summer of 2016 the school was renovated. The renovations include a new front entrance, new cafeteria lines, new HVAC units and upgrades to the auditorium. The renovations were funded by Fulton County SPLOST (Special Purpose Local Option Sales Tax) funds.

Centennial High School is one of two schools in Roswell, the other being Roswell High School.

Centennial has an award-winning media center, called the Learning Commons, managed by Dr. Christa Evans Heath. The facility has been selected as the model for all Fulton County schools to emulate.

Centennial High School enrolls approximately 1,700 students and has a staff of over 180. Parents help support the school's educational program through the Parent-Teacher-Student Association, Booster Club, and the Foundation of the Fine Arts.

Dr. Opie Blackwell became principal in 2023. Previous principals include Keynun Campbell and Dr. Anthony Newbold.

As of 2023, Centennial is 36.9% White, 22.3% African American, 33.2% Hispanic, 3.8% Asian, and 3.6% Multi-Racial.

Centennial High School offers five types of diplomas - College Preparatory, College Preparatory with Distinction, Career Technology, Career Technology with Distinction and Dual Seal. Centennial offers an Advanced Placement program, which has an 87% passing rate, and honors level courses. Also offered are on-campus joint enrollment courses and an off-campus post secondary options program. Career technology programs include electronic media production, health science, criminal justice, diversified technology, and EXCEL.

Centennial's literary arts magazine, Avalon, is an entirely student-run publication which publishes written and visual works submitted by Centennial students. It was first published in 1998, and was published bi-annually until 2001, when it began to be published annually. Avalon is a nationally recognized magazine, frequently receiving awards from the Columbia Scholastic Press Association. Writer Liam Connolly was an editor during the 2003–2004 year. The 2004–2005 issue received a Silver Crown award, and was the only literary magazine in Georgia to do so. The 2005-2006 issue received a Bronze Crown Award.

The official student newspaper is The Accolade. It published its first issue in the fall of 1997, the year that the school opened.

As of the fall of 2007, Centennial had teamed up with Score Atlanta and Turner Broadcasting to begin showing live broadcasts of the school's home sports games. This was the first program ever to do this with high school students.

Centennial's 2008 Model United Nations delegations of Albania and Venezuela placed first and third out of over 200 delegations in the National High School Model United Nations competition, with Albania coming in first, and Venezuela third respectively. In March 2009, Centennial competed again in the national competition, representing France, and repeated in first place out of over 250 schools.

In 2011, Centennial returned to the top ten, placing eighth in the nation. According to Best Delegate, "Centennial placed a distant third behind Port Charlotte High School and Gulf Coast High School at their hometown Georgia Tech GTMUN conference to begin the Fall, but the team roared back at Nationals NHSMUN to win Outstanding Large Delegation. We valued this win at one of the most competitive conferences in the nation much more than their early-season head-to-head placing at the smaller, regional GTMUN in determining where they would place in the standings — at the end of the season, Centennial won one of the top team awards in the circuit. On a side note, GTMUN Secretary-General Kelsie Riemenschneider is among its alumni in the college ranks."

Also in 2011, Centennial's Model UN team hosted its first Model UN Conference, called MiniMUN, for area middle school students. MiniMUN continues to expand and bring in middle school students from all over Georgia. The conference is entirely student-run.

In 2012, Centennial ranked ninth in the nation, according to Best Delegate: "Centennial continues to be one of the strongest teams from the Southeast. The team won Best Delegation at the Southern United States SUSMUN conference and placed third at an increasingly competitive Georgia Tech GTMUN. The team primarily participates at in-state conferences but teams around the country will recognize them when they travel to participate at Nationals NHSMUN (Centennial won a delegation award there last year)."

As of May 29, 2013, Best Delegate ranked Centennial's Model UN team number six in the nation. During the 2012–2013 school year, Centennial won the Award of Distinction at the National Model United Nations, the Best Small Delegation Award at the HMUN, the Award of Distinction at Southern States Model United Nations, and won more delegation awards at UGAMUN and Georgia Tech GTMUN.

In 2014 Centennial received both the Award of Excellence and the Research and Preparation Award of Excellence at NHSMUN. This was followed in 2015 and 2016 with the Award of Merit at the same conference.

In 2016–2017, the team competed at GTMUN, Vanderbilt's Model United Nations Conference XIII, Model Arab League, and UGAMUNC receiving several awards, including Best Position Paper, Honorable Mention and Outstanding Delegation awards for individual and overall delegations.

In the 2015–2016 school year, Centennial added a class in International Affairs designed to cultivate young delegates through mentorship and instruction by senior members of the team.

According Best Delegate's 2015-2016 high school rankings, Centennial MUN team ranks top 150 teams in the nation.

Centennial is advised by the Social Studies Department Chair Mack Hennessey.

The 2002 Knights football team went 10–0, marking the only undefeated regular season in Centennial's history. The region 6-AAAAA champion The Knights lost in the second round of the state playoffs to eventual state champion Parkview High School.

Centennial's first team state championship was won by the 2006 girls' varsity swim team.

Both Centennial's boys' and girls' varsity cross country teams qualified for the state meet eight years in a row, from 2007 to 2013. In 2010, the boys' and girls' varsity teams both finished first at the regional meet. Senior Brooke Koblitz led the girls' race and broke the school record for 3.1 miles, finishing at 18:40. Junior Kane Davis finished first in the boys' race. The team also sponsors the annual Firstgiving Sam Robb Memorial 5k and Fun Run which raises money for the Cure Childhood Cancer fund and honors former Centennial student Sam Robb.

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