कार्यालय या दफ्तर एक कमरा या इमारत होती है जिसका प्रयोग मुख्य रूप से लिपीकीय या प्रशासनिक कार्य करने के लिए किया जाता है। कार्यालय शब्द का प्रयोग किसी संगठन के अंतर्गत किसी विशेष ओहदे जिसके साथ कई विशिष्ट कर्तव्य समाहित हों, को भी निरूपित करता है, जैसे कि प्रधान मंत्री कार्यालय। साधारण शब्दों में कार्यालय वो स्थान है जहां लोग काम करते हैं।

An office is a space where the employees of an organization perform administrative work in order to support and realize the various goals of the organization. The word "office" may also denote a position within an organization with specific duties attached to it ; the latter is an earlier usage, office as place originally referring to the location of one's duty. In the adjective form, the term "office" may refer to business-related tasks. In law, a company or organization has offices in any place where it has an official presence, even if that presence consists of a storage silo, for example, instead of a more traditional establishment with a desk and chair. An office is also an architectural and design phenomenon, including small offices, such as a bench in the corner of a small business or a room in someone's home, entire floors of buildings, and massive buildings dedicated entirely to one company. In modern terms, an office is usually the location where white-collar workers carry out their functions.