A technical writer is a professional information communicator whose task is to transfer information between two or more parties, through any medium that best facilitates the transfer and comprehension of the information. Technical writers research and create information through a variety of delivery media (electronic, printed, audio-visual, and even touch). Example types of information include online help, manuals, white papers, design specifications, project plans, and software test plans. With the rise of e-learning, technical writers are increasingly becoming involved with creating online training material.

According to the Society for Technical Communication (STC):

Technical writing is sometimes defined as simplifying the complex. Inherent in such a concise and deceptively simple definition is a whole range of skills and characteristics that address nearly every field of human endeavor at some level. A significant subset of the broader field of technical communication, technical writing involves communicating complex information to those who need it to accomplish some task or goal.

In other words, technical writers take advanced technical concepts and communicate them as clearly, accurately, and comprehensively as possible to their intended audience, ensuring that the work is accessible to its users.

Kurt Vonnegut described technical writers as:

...trained to reveal almost nothing about themselves in their writing. This makes them freaks in the world of writers, since almost all of the other ink-stained wretches in that world reveal a lot about themselves to the reader.

Engineers, scientists, and other professionals may also be involved in technical writing (developmental editing, proofreading, etc.), but are more likely to employ professional technical writers to develop, edit and format material, and advise the best means of information delivery to their audiences.