山口洋市（印尼语: Kota Singkawang）是位于印度尼西亚西加里曼丹省北部的滨海城市，为西加省第二大城。

根据2007年的估计，山口洋的人口大约有197,079人。人口之中，华人亦称唐人约占62%，为主要民族，其次为马来族和达雅族，通行客语。2007年12月19日，黄少凡就任山口洋市长，成为该市第一位华裔市长。

Singkawang or San Keuw Jong (Chinese:山口洋; pinyin:Shānkǒuyáng; Hakka: San Khew Jong) is a city located in the province of West Kalimantan (or Kalimantan Barat), on the island of Borneo in Indonesia. It is located at about 145 km north of Pontianak, the provincial capital, and is surrounded by the Pasi, Poteng, and Sakok mountains. Singkawang is derived from Hakka Chinese, San Khew Jong which refers to "a town in hills nearby a sea and estuary."