实武牙（Sibolga）是印度尼西亚北苏门答腊省西部海岸的海港城市。其面向于印度洋，是去往尼亚斯岛的一个中转港。在2004年印度洋地震中遭受重创。

Sibolga (formerly sometimes Siboga) is a city and a port located in the natural harbour of Sibolga Bay on the west coast of North Sumatra province, in Indonesia. It is located on the western side of North Sumatra, facing the Indian Ocean and is a transit harbour to the Nias island which was hard hit during the 2004 Indian Ocean earthquake. The City has an area of 10.77 km and had a population of 84,444 at the 2010 Census.