Ziyuan may refer to:

• Ziyuan (字苑), or Essays on Chinese Characters, Chinese dictionary attributed to the Eastern Jin Dynasty scholar Ge Hong
• Ziyuan County (资源县), Guilin, Guangxi, China
  • Ziyuan Town (资源镇), town in and county seat of Ziyuan County
• Ziyuan (satellite), a series of Chinese satellites
• Ziyuan (子遠), style name of Xu You

• Proportionality constant
• Proportionality (mathematics)
• Proportionality (political maxim)
• Proportional (mathematics)
• Proportional representation
• Proportional Representation
• Proportional Representation Society
• Proportional Representation using the Single Transferable Vote
• Proportional Respresentation
• Proportional tax
• Proportion (architecture)
• Proportion (mathematics)
• Proporz
• Proposal
• Proposal (business)
• Proposal for the Province of Toronto
• Proposals for a Greater Serbian State
• Proposals for Amendments to the United States Constitution
• Proposals for amendments to the United States constitution
• Proposals for amendments to the U.S. Constitution
• Proposals for a Palestinian State
• Propose
• Proposed 1893 Constitution of the Kingdom of Hawaii
• Proposed Afghan Constitution
• Proposed amendments to the United States constitution