在线交易处理（OLTP, Online transaction processing）是指透过信息系统、电脑网络及数据库，以在线交易的方式处理一般即时性的作业数据，和更早期传统数据库系统大量批次的作业方式并不相同。OLTP通常被运用于自动化的数据处理工作，如订单输入、金融业务…等反复性的日常性交易活动。 和其相对的是属于决策分析层次的在线分析处理（OLAP）。

On line transaction processing, or OLTP, is a class of information systems that facilitate and manage transaction-oriented applications, typically for data entry and retrieval transaction processing. The term is somewhat ambiguous; some understand a "transaction" in the context of computer or database transactions, while others (such as the Transaction Processing Performance Council) define it in terms of business or commercial transactions. OLTP has also been used to refer to processing in which the system responds immediately to user requests. An automated teller machine (ATM) for a bank is an example of a commercial transaction processing application. On line transaction processing applications are high throughput and insert or update-intensive in database management. These applications are used concurrently by hundreds of users. The key goals of OLTP applications are availability, speed, concurrency and recoverability. Reduced paper trails and the faster, more accurate forecast for revenues and expenses are both examples of how OLTP makes things simpler for businesses. However, like many modern on line information technology solutions, some systems require offline maintenance, which further affects the cost–benefit analysis of on line transaction processing system.