- January 3 to 7 - Boko Haram commits a series of mass killings in the northeastern Nigerian town of Baga and its environs, in the state of Borno. Between 150 and 2,000 people are killed in total.
- January 23 - Salman bin Abdulaziz al Saud ascends to the throne of Saudi Arabia.
- February 6 - The Houthis take control of Sana'a, the capital of Yemen.
- March 26 - The House of Saud enters the Yemeni Civil War.
- April 2 - Gunmen from Al-Shabaab storm the Garissa University College in Garissa, Kenya, killing 148 people and injuring 79 or more.
- May 28 - Dennis Hastert is indicted on federal charges of structuring bank withdrawals to evade bank reporting requirements and making false statements to federal investigators.
- May 29 - Muhammad Buhari is elected President of Nigeria for the second time.
- June 14 - Dee Dee Blanchard is killed at her home in Greene County, Missouri by her daughter Gypsy Rose Blanchard and Nicholas Godejohn.
- June 15 - The Palestinian Unity Government collapses.
- June 15 to July 11 - Boko Haram commits a series of suicide bombings in N'Djamena, Chad, killing 59 people total.
- June 17 - White supremacist Dylann Roof kills nine people in a racially-motivated mass shooting at the Emanuel African Methodist Episcopal Church in Charleston, South Carolina.
- July 23 - Grand 16 movie theater shooting
- July 24 - Peace negotiations between Turkey and the Kurdistan Workers' Party break down. President Recep Tayyip Erdoğan launches Operation Martyr Yalçın against both the PKK as well as against the Islamic State.
- August 26 - News reporter Alison Parker and photojournalist Adam Ward are fatally shot by former reporter Vester Lee Flanagan while conducting a live television interview near Smith Mountain Lake in Moneta, Virginia.
- October - American rapper Tekashi 6ix9ine pleads guilty to three counts of use of a child in a sexual performance and is sentenced to four years probation and 1000 hours of community service.
- October 1 - Umpqua Community College shooting
- October 12 - Atomwaffen Division is founded.
- October 22 - Trollhättan school attack
- October 31 - Metrojet Flight 9268 is destroyed by a bomb over the northern Sinai en route to St. Petersburg, Russia. All 224 passengers and crew who were on board were killed. The Islamic State's Sinai Branch, previously known as Ansar Bait al-Maqdis, claim responsibility for the incident.
- November 5 - John Magufuli is sworn in as President of Tanzania.
- November 13 - November 2015 Paris attacks
- November 27 - Colorado Springs Planned Parenthood shooting
- December 31, 2015 - January 1, 2016 - 2015–16 New Year's Eve sexual assaults in Germany
- April 30 - Cannon Hinnant
- January 23 - Abdullah bin Abdulaziz al Saud
- March 23 - Lee Kuan Yew
- April 19 - Aliaskhab Kebekov
- April 29 - Dan Walker
- May 9 - Kenan Evren
- May 24 - Michael W. Ryan
- June 5 - Tarek Aziz
- June 14 - Dee Dee Blanchard
- July 23 - John Russell Houser
- August 7 - Manuel Contreras
- August 18 - Abu Muslim al-Turkmani
- August 26 - Vester Lee Flanagan
- October 1 - Christopher Harper-Mercer
- October 22 - Anton Lundin Pettersson
- October 28 - Pazuzu Algarad
- October 31 - Gus Savage
- November 5 - Czesław Kiszczak
- November 12 - Jihadi John
- February 6 - Kayla Mueller
- July 13 - Sandra Bland
- August 26 - Alison Parker and Adam Ward
- November 3 - Jeremy Mardis and Christopher Few