Google Image Search is a search (search engine) service created by Google which allows users to search the Web (World Wide Web) for image content. The feature was originally introduced in July 2001. The keywords (Keyword (Internet search)) for the image search are based on the filename of the image, the link text pointing to the image, and text adjacent to the image. When searching for an image, a thumbnail of each matching image is displayed. Then when clicking on a thumbnail, the image is displayed in a frame at the top of the page and the website on which that image was found is displayed in a frame below it, making it easier to see from where the image is coming.

In early 2007 Google implemented an updated user interface for the image search, where much of the information about the image was hidden until the user moused over the thumbnail. This feature was discontinued after a few weeks. It is now Google Images.

On October 27, 2009, Google image search added an important and useful feature to its image search, which is called finding similar images.