Heyang County (simplified Chinese: 合阳县; traditional Chinese: 合陽縣; pinyin: Héyáng Xiàn, 郃陽) is a county in Shaanxi Province, China, bordering Shanxi Province to the east across the Yellow River.

It is under the administration of the prefecture-level city of Weinan.

Heyang County dates to at least the early Han, when Liu Bang's elder brother Liu Xi was demoted to being its marquess after fleeing a Xiongnu attack on Dai c. 200 BC.

A species of stone loach, Triplophysa heyangensis, is named after Heyang County where it was first discovered.

This Shaanxi location article is a stub.