Borommaratchachonnani Road (Thai: ถนนบรมราชชนนี, RTGS: Thanon Borommaratchachonnani, pronounced [tʰā.nǒn bɔ̄ː.rōm.mā.râːt.t͡ɕʰā.t͡ɕʰōn.nā.nīː]), is a main road in Bangkok's Thonburi side (i.e. the west bank of Chao Phraya River) and Bangkok Metropolitan Region. The majority of the road constitutes Highway 338 (ทางหลวงแผ่นดินหมายเลข 338).

Borommaratchachonnani Road has a starting point at the Borommaratchachonnani Intersection in the areas of Bangkok Noi and Bang Phlat's Pinklao neighbourhood in Bangkok. It then heads to the west through Taling Chan and Thawi Watthana, extending past the localities of Phutthamonthon, Sam Phran in Nakhon Pathom and terminates at the intersection with Petchkasem Road in the area of Nakhon Chai Si. The total length of the road is 33.984 km (21.117 mi).

The road as it is today originated from the opening of Phra Pinklao Bridge across to Phra Nakhon area in 1973. The bridge was extended upon by the construction of the Somdet Phra Pinklao Road from the foot of the bridge linking it to Charansanitwong Road. It was later expanded to form the Bangkok Noi-Nakhon Chai Si Highway (ทางหลวงสายบางกอกน้อย-นครชัยศรี) in 1979 and completed in 1984. At first, the road had no officially designated name, therefore it was informally referred to as Pinklao-Nakhon Chai Si Road (ถนนปิ่นเกล้า-นครชัยศรี). It wasn't until the year 1991 that King Bhumibol Adulyadej (Rama IX) graciously named the road "Borommaratchachonnani" ('King's mother') in honour of his mother, Princess Srinagarindra.

In 1998, a parallel Borommaratchachonnani Elevated Highway was opened to alleviate traffic jams. The total length of the elevated road is 14 km (8.6 mi).

Borommaratchachonnani Road runs adjacent to many notable establishments and locations such as Lotus's Pinklao, Central Plaza Pinklao, Chaophraya Hospital, the Southern Bus Terminal, Southern Railway, Princess Maha Chakri Sirindhorn Anthropology Centre, Thongsuk College, Thonburi 2 Hospital, Phutthamonthon, Mahidol University main campus and Prince Mahidol Hall, the Thai Human Imagery Museum etc.

Moreover, the road serves as the location of Borommaratchachonnani Depot, the main terminal and depot of BMTA's bus zone 6, which provides a total of 18 routes. It is located on the eastbound side near Khukhanan Loi Fah [Parallel Elevated Highway] Police Station in Thawi Watthana. It moved from the original location, Phutthamonthon Sai 2 Road in Bang Khae with services first commencing on April 1, 2019.

• Department of Highways (2013-05-27). "ถนนบรมราชชนนี" [Borommaratchachonnani Road]. facebook (in Thai). Retrieved 2019-04-04.
• "โครงการก่อสร้างทางคู่ขนานลอยฟ้าถนนบรมราชชนนี". Department of Public Works website (in Thai). Bangkok Metropolitan Administration. Retrieved 22 October 2019.
• "โครงการ ทางคู่ขนานลอยฟ้าถนนบรมราชชนนี". km.rdpb.go.th (in Thai). Office of Royal Development Projects Board. Retrieved 22 October 2019.
• Padawangi, Rita (2018). Routledge Handbook of Urbanization in Southeast Asia. Routledge. ISBN 9781134799770.
• The Wisdom of the Monarch: A World Leader in Sustainable Development (PDF). The Committee of the Royal Tribute Project of the National Legislative Assembly to Compile Laws Supporting Royal Initiated Projects. 2018. pp. 223–229.
• Jittiwasurat, Pornchai; Rattanathavorn, Tapanee (31 March 2018). "Urban morphological transformation of riverfront communities in the Nakhon Chaisri Basin, Thailand". Manusya Journal of Humanities. 21 (1): 85–105. doi:10.1163/26659077-02101005. Retrieved 22 October 2019.
• "ขสมก. เปิดแล้ว "อู่บรมราชชนนี" ประหยัดค่าเช่าที่ดิน ทำใจสาย 79-101 ไม่เข้าพุทธมณฑล สาย 2". Manager Online (in Thai). 31 March 2019. Retrieved 23 October 2019.

13°46′53.71″N 100°25′20.04″E / 13.7815861°N 100.4222333°E / 13.7815861; 100.4222333