|Initial release||August 12, 2014|
Google Classroom is a free blended learning platform developed by Google for educational institutions that aims to simplify creating, distributing, and grading assignments. The primary purpose of Google Classroom is to streamline the process of sharing files between teachers and students. As of 2021, approximately 150 million users use Google Classroom.
Google Classroom integrates a variety of other Google Applications for Education, such as Google Docs, Google Sheets, Google Slides, Gmail, and Google Calendar into a cohesive platform to manage student and teacher communication. Students can be invited to join a class through a private "class code" or be imported automatically from a school domain. Teachers can create, distribute and mark assignments all within the Google domain. Each class creates a separate folder in the respective user's Google Drive, where the student can submit work to be graded by a teacher. Assignments and due dates are added to Google Calendar, where each assignment can belong to a category or topic. Teachers can monitor each student's progress by reviewing revision history of a document, and after being graded, teachers can return work along with comments and grades.
Google Classroom has undergone a series of updates and changes since its original release in May 2014.
|May 6, 2014||Google Classroom was announced with a preview available for some members of Google's G Suite for Education program.|
|August 12, 2014||Google Classroom was released publicly. |
|2015||Google announced a Classroom API and a share button for websites, allowing school administrators and developers to further engage with Google Classroom.Google integrated Google Calendar into Classroom for assignment due dates, field trips, and class speakers.|
|2017||Google opened Classroom to allow any personal Google users to join classes without the requirement of having a G Suite for Education account, and in April of the same year, it became possible for any personal Google user to create and teach a class.|
|2018||Google introduced a major redesign to Classroom. This included adding a new classwork section, improving the grading interface, allowing reuse of classwork from other classes, and adding features for teachers to organize content by topic.|
|2019||Google introduced 78 new illustrated themes and the option to drag and drop topics and assignments in the classwork section.|
|2020||Google added integration with Google Meet so that teachers can have a unique meet link within each class. In addition, several features were added to classroom, with Google stating "as educators worldwide have reinvented their practice online, we’re also adapting our tools to meet the evolving needs of their new educational landscape." These updates included:
Google Classroom also saw a sharp increase in usage as a result of the COVID-19 pandemic in which many schools shifted to remote education options. Specific research programs also used Google Classroom to engage in authentic learning from around the world. 
Google Classroom integrates several Google Applications for Education (GAPPS) such as Google Drive, Google Docs, Google Sheets, Google Slides, Google Forms, Google Sites, Gmail to help educational institutions transition to a virtual, paperless system. Google Calendar was later added to help with assignment due dates, field trips, and class speakers. Students can be invited to classrooms through the institution's database, through a private code that can then be added in the student's user interface or automatically imported from a school domain. Each class created with Google Classroom creates a separate folder in the respective user's Google Drive, where the student can submit work to be graded by a teacher.
Assignments are stored and graded on Google's suite of productivity applications that allow collaboration between the teacher and the student or between students. Instead of sharing documents that reside on the student's Google Drive with the teacher, files are hosted on the student's Drive and then submitted for grading. Teachers on Google Classroom have the option of creating Assignments in various templates and formats with different accessibility options: "student can view file," "student can edit file," or "make a copy for each student". These assignments can be submitted for a grade and teacher feedback. Students can also choose to attach additional documents from their Drive to the assignment. Set assignments appear on the 'To do' list.
Google Classroom supports many different grading schemes. Teachers have the option to attach files to the assignment which students can view, edit, or get an individual copy. Students can create files and then attach them to the assignment if a copy of a file wasn't created by the teacher. Teachers have the option to monitor the progress of each student on the assignment where they can make comments and edit. Turned in assignments can be graded by the teacher and returned with comments to allow the student to revise the assignment and turn back in. Once turned in, assignments can only be edited by the teacher unless the teacher turns the assignment back.
Announcements can be posted by teachers to the class stream which can be commented on by students allowing for two-way communication between the teacher and students. Students can also post to the class stream but won't be as high a priority as an announcement by a teacher and can be moderated. Multiple types of media from Google products such as YouTube videos and Google Drive files can be attached to announcements and posts to share content. Gmail also provides email options for teachers to send emails to one or more students in the Google Classroom interface. Classroom can be accessed on the web or via the Android and iOS Classroom mobile apps.
Originality report was introduced in January 2020. It allows educators and students to see the parts and sections of the submitted work which contains the exact or similar wording to that of another source. For students, it highlights source materials and flags missing citation to assist the student in improving their writing. Teachers can also view the originality report, allowing them to verify the academic integrity of the student's submitted work. On G Suite for Education (free), teachers can turn on originality report for 3 assignments but have limited cloud storage. This restriction is lifted on G Suite Enterprise for Education (paid).
Classroom allows instructors to archive courses at the end of a term or year. When a course is archived, it is removed from the homepage and placed in the Archived Classes area to help teachers keep their current classes organized. When a course is archived, teachers and students can view it, but won't be able to make any changes to it until it is restored.
Google Classroom mobile apps, introduced in January 2015, are available for iOS and Android devices. The applications let users take photos and attach them to their assignments, share files from other apps, and support offline access, easing accessibility for users.
eLearning Industry tested and made a review of Google Classroom, in which they highlighted many positive and negative aspects. Among Classroom's strengths, the review highlighted ease of use, universal device accessibility, use of Google Drive as an effective way for teachers to quickly share assignments with students, the paperless process meaning the end of printing, handing out, and potentially losing work, and the fast feedback system between students and teachers. Among Classroom's disadvantages, the review highlighted the service's heavy integration of Google apps and services with limited or no support for external files or services, lack of automated quizzes and tests, and a lack of live chats that can aid in feedback efforts. Google Classroom won a 2020 Webby Special Achievement Award.
Due to the prominence of Google, students find Google Classroom easy to navigate since many are familiar with Google layout. Furthermore, the mobile app for Google Classroom functions well which has been praised by students. If notifications are enabled, the mobile app for Google Classroom can provide push notifications to remind students of upcoming deadlines, a feature that has been received well by students.
Additional research has shown the benefits of using Google Classroom in a blended learning model such as developing self-efficacy skills and attaining learning outcomes. 
As a company, Google has been criticized on several different issues, including privacy. Specific criticism of Google Classroom generally focuses on concern for privacy for students and Google's use of student data. Criticism of Google Classroom is often combined with criticism of Chromebooks and Google Workspace.
Other criticisms directed at Google Classroom are lack of a full-fledged grade book, lack of automatic quizzes and tests (common features in learning management systems), and editing of assignments once they are released. Students have also expressed a desire for personalization due to the Google Classroom layout being very simplistic and unappealing. Also, the chronological setup has been criticized as students respond with frustrations of having to scroll through to find past announcements.
Countries abroad used Google Classroom during the COVID-19 pandemic and pivoted to online learning systems to facilitate learning opportunities. While this provided equitable access to students and exposed learners to current and relevant online platforms, it also posed challenges such as unreliable internet connections, high costs of technology, and a lack and unavailability of training to use the platform.
Similarly to other online education platforms, adopting a fully remote or online education system brings forward socio-economic challenges such as access to technology in remote and lower socio-economic society areas. In studies discussing use of Google Classroom for English as a foreign language studies, students had positive perceptions towards using Google Classroom tools to learn about grammatical concepts and collaborate with others using student-to-student interactions and collaborative feedback.