Techo International Airport (IATA: KTI, ICAO: VDTI) is an international airport currently under construction in Kandal Province of Cambodia. Located about 30–40 kilometres (16–22 NM; 19–25 mi) south of Phnom Penh, the first phase is expected to be operational by 2025 and will replace the existing Phnom Penh International Airport as the city's main aviation hub. It is planned to span over 2,600 hectares (6,400 acres) in Kandal Province, and once completed, it will be the ninth largest airport in the world and designated as a 4F class airport.

The name Techo (Khmer: តេជោ) is a title given to army commanders by the King of Cambodia and Takhmao (Khmer: តាខ្មៅ) refers to the guardian spirit (Neakta) of Krong Takhmao which is the provincial city of Kandal province, the province in which the airport is located.

Then Prime Minister Hun Sen announced the new name on 9 December 2021 while inspecting the new airport. The word "Techo" is referenced from Khmer history in which the king granted titles to former Khmer army commanders Techo Meas and Techo Yort who operated in the territory of Kandal Province. He also stated that "Techo" shows the strength of the kingdom's monarchy.

Techo International Airport is being constructed in the south of Kandal province near the border of Takeo province, being 30-40 kilometers south of the capital city of Phnom Penh. The entire site is in front of the nearby Boeng Cheung Loung lake and is surrounded by rice fields.

A highway is being constructed to connect the airport to the southern part of Hun Sen boulevard. The current boulevard merges into National Highway 2, but will extend further south. The road will be 60 m wide and 13.5 km long. In July 2023, construction on it was almost halfway through, and by February 2024 it was 85% complete. The road is expected to be complete by 2024.

In July 2023, Sun Chanthol of the Ministry of Public Works and Transport expressed the government's interest in connecting the airport with Phnom Penh city, possibly near the AEON mall in Mean Chey, via light rail, potentially as part of an underground metro system.

The entire project is expected to cost around $1.5 billion, while the vast majority ($1.1 billion) was supposed to have been acquired from the China Development Bank. However an agreement signed in 2018 when the airport was announced was revoked. In order to compensate, the Cambodia Airport Investment Co., Ltd (CAIC) began issuing bonds in November 2021. This was subscribed mostly by local Cambodian insurance companies and banks, allowing the CAIC to raise $300 million, which is then invested by the OCIC. The Overseas Cambodian Investment Corporation (OCIC) has since stated that all of the $500 million budget originates entirely from Cambodia. The airport's design is being carried out by the British company Foster & Partners while construction is being undertakened by Chinese companies; with the China Construction Third Engineering Bureau Group Co., Ltd building the terminals; and the Shanghai Baoye Group - a subsidiary of Metallurgical Corporation of China - is constructing the runways, taxiways, aprons and related facilities.

In December 2023, about 22 Japanese companies began considering investment into the project, with firm representatives visiting the airport on 20 December. This followed a recent visit by Prime Minister Hun Manet to Japan, which according to The Phnom Penh Post helped attract interest in investing into Cambodia.

A new airport for Phnom Penh was first hinted in 2016 once further expansion plans for the existing Phnom Penh airport ended. The project was then officially announced in January 2018, with construction beginning in 2019. The $1.5 billion project is being invested by the CAIC, whilst the China Construction Third Engineering Bureau Group Co., Ltd is constructing the airport. The construction is taking place on 2,600 hectares of land in Kandal and Takeo provinces. Hun Sen announced the name for the airport on 9 December 2021 whilst inspecting the new airport.

By December 2021, the phase 1 was 27% complete and was thought to be complete by 2023. However, on March 30, 2023, the Deputy Governor of Kandal Province, Nou Peng Chandara, stated that the airport was now 44% complete during a press conference. By this point, nearly $700 million had been spent. On 30 June 2023, the State Secretariat of Civil Aviation (SSCA) announced that more than half of construction on phase 1 was completed. By the end of November 2023, the SSCA announced phrase 1 to be 55% completed. By January 2024, the Phrase 1 passenger terminal by China Construction Unit III was 47.4% completed, the power supply centre was 73.7%, parking lots by Shanghai Baoye (Cambodia) was 52.2%, and the traffic control tower by Cana Sino Construction Corporation was 90.8% done. On 8 February, Sin Chanserivutha, the Undersecretary of State and Spokesperson for Civil Aviation, announced that it was now over 64% complete.

The first phase was initially expected to be completed by mid-2024, with the airport being built in 3 stages. However, the opening has since been delayed to 2025. Both phase 1 and 2 are under construction.

On 8 June 2023, local residents from four communes in Kandal province around the airport protested against the filling of land near their homes and Canal 94. The residents feared that the companies constructing Techo Airport would demolish their homes. Chiv Kok Say, who is in-charge with land acquisitions, said the homes they were filling in were vacant after their owners were paid $2,000. Chiv also said that the developments there was to prevent future flooding of the airport. To prevent the residents from intervening, the company brought in security and fire trucks, which they used to spray water at the villagers who were armed with sticks and stones. Similarly, there were tensions between OCIC and farmers in Bati district over canals dug by the OCIC in August 2021. Local protests against the canal construction at the time was blocked by district and provincial police.

Since construction on the airport began, the OCIC began buying out land from local farmers. However, this was at a low rate of $1 per square meter, lower than the $5 and later $3 rates proposed by some local farmers and not adequate enough for some farmers to relocate to new farmland. The village chiefs and around 100 families in Champei and Doung communes in Bati district who have been farming on the land since 1979, then asked for Hun Manet to help mediate and increase the rate to $3. Their land is planned to be turned into a reservoir according to Chiv Kok Say, who also said that their request of a $3 rate was not feasible because their "farmlands were without title deeds".

On 28 January 2024, around 80 villagers from Ampov Prey, Kadal Stueng, gathered near land allocated for the airport and called on authorities to expedite a settlement process. In response, district governor Ouch Sao Voeun said that the land they were demanding compensation for was already compensated to its alleged owner, a Phnom Penh resident. However, the villagers have claimed that they were the actual owners and have been farming on it since 1984.

More than 400 families in Kadal Stueng and Bati districts are expected to be displaced by the airport's development.

Foster and Partners has said that the airport's design is aimed to be one of the world's greenest airports. The terminals have been designed to use natural light, and have lush greenery. The terminals will also almost entirely be powered by an onsite solar farm. For the Cambodian government, the inclusion of greenery is part of the GreenSky project, which aims to make Techo a sustainable and eco-friendly airport. GreenSky aims to do this through the use of vertical gardens, rooftop greenery, and the use of native Cambodian flora, which will improve the airport's air quality. The project also aims to establish a botanical garden within the airport. Alongside the use of flora, the airport management also plans to use eco-friendly practices such as the use of solar energy, rainwater harvesting, and measures to reduce waste.

Techo Airport is planned to replace all of Phnom Penh International Airport's commercial operations and international flights, while the old airport will be used as a military airbase, for domestic flights, private jets, diplomats & foreign leaders. The first phase is set to handle 13 million passengers a year, whilst the second phase is set to increase this to 30 million. Altogether, the three phases will be able to handle 50 million passengers a year. The airport will be able to handle Airbus A330s and A350s; and long-ranged Boeing planes once phase 1 is finished. By 2024, Techo Airport is expected to be able to handle 175,000 tonnes of cargo.

Each of the three phases of construction will include a 4 kilometer runway capable of handling large long-haul aircraft.

• List of airports in Cambodia
• List of airlines of Cambodia