信用证（Letter of Credit，常用缩写：L/C），是国际结算的一种主要的结算方式。因其为银行风险而非商业风险，较为安全可靠，故广泛被采用为交易方法，但相对地，信用状的相关费用较高，形成交易成本的增加。

信用证的开具必须由付款人向银行申请。开证行在付款人缴纳开证费用和保证金之后，开证行会开具信用证，保证在符合一定条件的情况下向受益人付款。根据开具方式的不同，可以分为信开信用证和电开信用证两种。信开信用证是指开证行开具纸质信用证，并且上面盖章和加编密押，通过邮寄的形式送达通知行。电开信用证是指开证行在信用证上面加编密押之后通过电传的形式送达通知行。

A letter of credit is a document, typically from a bank (Issuing Bank), assuring that a seller (Beneficiary) will receive payment up to the amount of the letter of credit, as long as certain documentary delivery conditions have been met. In the event that the buyer (Applicant) is unable to make payment on the purchase, the Beneficiary may make a demand for payment on the bank. The bank will examine the Beneficiary's demand and if it complies with the terms of the letter of credit, will honor the demand.