Line 16 of the Beijing Subway (Chinese: 北京地铁16号线; pinyin: běijīng dìtiě shíliù hàoxiàn) is a rapid transit line in Beijing. It is 48.9 km (30.4 mi) in length with 30 stations. The line is fully underground.

Construction began in December 2013. The northern section, from Bei'anhe to Xiyuan, was opened on 31 December 2016. An infill station, Nongda Nanlu, was opened on 30 December 2017. It extended to Ganjiakou on 31 December 2020, and extended to Yuyuantan East Gate on 31 December 2021. The southern section to Yushuzhuang opened on 31 December 2022. The remainder of the line to Wanpingcheng opened on 30 December 2023.

The line is operated by the Beijing MTR Corporation Limited and uses CNR Changchun DKZ93 and CSR Sifang SFM40 eight-car high-capacity wide-body Type A trains. Line 16's color is dark-moderate green.

The line starts at the west end of Beiqing Road (北清路), just outside of the 6th Ring Road, and follows the road east to Yongfeng Road (永丰路) where it turns south towards the city. Line 16 follows Yongfeng Road south to Xiyuan, then continues south to the National Library and Yuyuantan Dongmen (Yuyuantan Park East Gate). It then continues south, passing through Muxidi, Daguanying, and turns west through Fengtai railway station, then west-southwest through Yushuzhuang before traversing slightly west north-west to end at Wanpingcheng.

In 2009, Line 16 was among the 198 major urban planning projects listed by Beijing's development and reform commission. At that time, Line 16 was slated to run about 35 km (21.7 mi), from Huilongguan in Changping District to Huaxiang in Fengtai District.

According to the June 2010 plans, the northern section of Line 16 will replace the originally planned Line 4 northern extension and run 48 km (29.8 mi) from Bei'anhe in Haidian District, south to Xiaoyueyuan, near the Lugou Bridge in Fengtai District. The line would begin near Bei'anhe, and provide access to parts of Haidian, north of the foothills the Western Hills that extend into Haidian District. For this reason, that section of the line was also referred to as the Haidian Shanhou (literal translation: Haidian Back Mountain) Line because it begins on the backside of the low-lying range that extends from the Fragrant Hills to the Summer Palace. Points of interest that the line may pass along the route to Xiaoyueyuan in the south include the Summer Palace, Haidian Gymnasium, National Library, Purple Bamboo Park, Beijing Zoo, Chegongzhuang West Road, Sanlihe, Wanshou Temple, Lize Shangwuqu (Lize Business District), and the Beijing Fengtai railway station. The proposal was scaled back with the removal of the Haidian Shanhou section in December 2010, reducing the line to just 23 km (14.3 mi), from Suzhou Jie to Wanpingcheng. But the northern section was subsequently restored months later, bringing the line length 49 km (30.4 mi).

The Beijing Municipal Commission of Urban Planning released the plans for several subway stations in 2013. Construction of the line began in December 2013.

On 28 November 2015, the Concession Agreement for Line 16 was signed by the Beijing Municipal Government and BJMTR. Line 16 is a PPP project and BJMTR would participate in the investment, operations and maintenance of the new line. Under the Concession Agreement, BJMTR would undertake the operations and maintenance of Line 16 for a term of 30 years. The Beijing Municipal Government is responsible for the investment and construction of Part A (tunnels, station structure etc.), while BJMTR invested 14.5 billion RMB and is responsible for investing in and constructing Part B of the Line 16 project (rolling stocks, signaling systems, ticket machines etc.).