In the city's Castro District, six people were arrested, including one for possession of an illegal weapon, one for robbery, one for an outstanding warrant, two for driving under the influence of drugs or alcohol, and one for being drunk in public, police Sgt. Wilfred Williams said.
In the South of Market neighborhood, one person was cited for battery, three people were cited for open containers of alcohol, and three were cited for drinking in public, Williams said.
Elsewhere in the city, seven misdemeanor arrests were made, as well as 16 for people being drunk in public, according to Williams.
A 22-year-old San Francisco man was killed in the Bayview District in an incident not related to Halloween celebrations.
No one has been arrested in connection with the shooting, which occurred at about 7:50 p.m. near the intersection of Griffith Street and Navy Road, police said.
There have been problems historically on Halloween in San Francisco, particularly in the Castro District where five people were stabbed in 2004 and 2005, and in 2006 when nine people were shot.
The city instituted the Home for Halloween campaign in 2007 to curb the increased violence and vandalism, and no major acts of violence have been reported in the area the past three years.