York South—Weston (French: York-Sud—Weston) is a federal electoral district in Ontario, Canada, that has been represented in the House of Commons of Canada since 1979.

In 2015, York South—Weston elected Canada's first MP of Somali descent, Ahmed Hussen.

Under the 2022 Canadian federal electoral redistribution the riding will be renamed York South—Weston—Etobicoke.

Located in the west-end of Toronto, the riding is made up largely of the old City of York, a southwestern portion of the old city of North York, and parts of the old city of Toronto north of High Park. A sizeable portion of the land in the western part of the riding which was previously part of the old City of York was the old village of Weston until that village was absorbed into the City of York in 1968. The riding has a largely working class and immigrant population.

Its geographic boundaries are the part of the City of Toronto bounded by a line drawn from Humber River east along Highway 401, south along the Canadian National Railway situated west of Caledonia Road, west along Rogers Road, southeast along Old Weston Road, west along Lavender Road, south along Keele Street, southeast along the Canadian National/Canadian Pacific Railway, west along the Canadian Pacific Railway, and north along the Humber River to Highway 401.

York South—Weston was created in 1976 from parts of York South, York West, Davenport, High Park—Humber Valley, and Etobicoke ridings.

Its new boundaries were originally of the part of Metropolitan Toronto bounded by a line drawn from Eglinton Avenue West north along Keele Street, west along Lawrence Avenue West, south along the Humber River, east and north along the north limit of the City of Toronto, south along Runnymede Road, east along Annette Street, south along Keele Street, east along Humberside Avenue, northwest along the Canadian National Railway, east along the north limit of the City of Toronto, north along the east side of Prospect Cemetery, and west along Eglinton Avenue West to Keele Street.

In 1987, York South—Weston was redefined to consist of the parts of the cities of North York, Toronto and York bounded by a line drawn from the western limit of the City of North York east along Highway 401, south along Keele Street, west along Eglinton Avenue West, south along Keele Street, west along the southern limit of the City of York, southeast along the Canadian National Railway line, west along Dupont Street, northwest along Dundas Street West, west along Annette Street, north along Runnymede Road, west along the Canadian Pacific Railway line, and north along the western limits of the Cities of York and North York to Highway 401.

In 1996, it was redefined to consist of the parts of the cities of North York, Toronto and York bounded by a line drawn from the western limit of the City of North York east along Highway 401, southeast along the Canadian National Railway situated immediately west of Caledonia Road, west along Rogers Road, south along Old Weston Road, west along the northern limit of the City of Toronto, southeast along the Canadian National Railway, west along the Canadian Pacific Railway, and north along the western limit of the cities of York and North York to Highway 401.

In 2003, it was given its current boundaries as described above. This riding was unchanged during the 2012 electoral redistribution.

• 
  1976 to 1987
• 
  1987 to 1996
• 
  1996 to 2003
• 
  2003 to 2015

According to the 2021 Canadian census; 2013 representation

Languages: 49% English, 9.8% Portuguese, 7.2% Spanish, 4.8% Italian, 3.2% Tagalog, 3.1% Vietnamese, 2.1% Somali, 1% Yue
Religions: 65.9% Christian (41.2% Catholic, 2.8% Pentecostal, 2.3% Christian Orthodox, 1.7% Anglican, 1% Baptist), 18.5% No religion, 8.7% Muslim, 3% Buddhist, 2.6% Hindu
Median income (2020): $34,400
Average income (2020): $43,360

Ethnicity groups: White: 41.2%, Black: 24%, Latin American: 9.1%, Filipino: 6.8%, South Asian: 5.7%, Southeast Asian 4.6%, Chinese: 1.9%

Ethnic origins: Portuguese 12.2%, Italian 11%, Filipino: 6.2%, Canadian 6%, Jamaican 5.1%, English 4.4%, African 4.2%, Vietnamese 4.2%, Irish 4%, Scottish 3.6%

This riding has elected the following members of the House of Commons of Canada:

Parliament	Years	Member		Party
York South—Weston Riding created from York South, York West, Davenport, High Park—Humber Valley and Etobicoke
31st	1979–1980		Ursula Appolloni	Liberal
32nd	1980–1984
33rd	1984–1988		John Nunziata
34th	1988–1993
35th	1993–1996
	1996–1997			Independent
36th	1997–2000
37th	2000–2004		Alan Tonks	Liberal
38th	2004–2006
39th	2006–2008
40th	2008–2011
41st	2011–2015		Mike Sullivan	New Democratic
42nd	2015–2019		Ahmed Hussen	Liberal
43rd	2019–2021
44th	2021–present