A webmaster (portmanteau of web and postmaster), also called a web architect, web developer, site author, website administrator, or (informally) webmeister, is a person responsible for maintaining a website(s). The duties of the webmaster may include ensuring that the web servers, hardware and software are operating accurately, designing the website, generating and revising web pages, replying to user comment, and examining traffic through the site.

Webmasters may be generalists with HTML expertise who manage most or all aspects of Web operations. Depending on the nature of the websites they manage, webmasters typically know scripting languages such as PHP, Perl and Javascript. They may also be required to know how to configure web servers such as Apache and serve as the server administrator.

An alternative definition of webmaster is a businessperson who uses online media to sell products and/or services. This broader definition of webmaster covers not just the technical aspects of overseeing Web site construction and maintenance but also management of content, advertising, marketing and order fulfilment for the Web site.

Core responsibilities of the webmaster may include the regulation and management of access rights of different users of a website, the appearance and setting up website navigation. Content placement can be part of a webmaster's responsibilities, while content creation may not be.