Tandem Diabetes Care is a public US medical device manufacturer based in San Diego, CA. The company develops medical technologies for the treatment of diabetes and specifically insulin infusion therapy.

In 2006, a group of engineers recognized the need for new and improved methods of pumping insulin and incorporated as Phluid, Inc. In 2007, Kim Blickenstaff joined the organization as President and CEO, bringing his philosophy of using market research as the inspiration for product development and started on the development of the t:slim Insulin Pump. In 2008, this predecessor company became the newly incorporated Tandem Diabetes Care, Inc. that was formed with a focus on promoting a comprehensive, user-centric, and integrated approach to diabetes product development and customer care. Tandem Diabetes Care felt that incorporating enhanced ease of use and attractive design—often associated with consumer electronics development—would also encourage more patients to consider the clinical benefits of insulin pump therapy. Tandem Diabetes Care interviewed more than 4,000 insulin pump users and health care providers to design its first device, the t:slim Insulin Pump.

In 2016, the company was ranked #39 on the Deloitte Fast 500 North America list.

In November 2011, the company received FDA clearance to market the t:slim Insulin Pump, the first ever touch-screen insulin pump. In February 2013, the company received FDA clearance to market the t:connect Diabetes Management Application, a Mac and PC-compatible data management application that provides t:slim Pump users and their healthcare providers a way to display data from the pump and supported blood glucose meters on a cloud-based platform. In January 2015, Tandem announced FDA clearance of the t:flex Insulin Pump, the largest capacity insulin pump on the market. In July 2014, Tandem announced that it had submitted a PMA for the t:slim G4, which integrates t:slim Pump technology with the Dexcom G4 Platinum CGM System. This device was approved by the FDA in September 2015. The FDA approved a tool to update the software on Tandem's pumps in July, 2016. The Tandem Product Updater is designed to deliver software updates to Tandem's pumps to provide new features and interface improvements. In announcing the approval, Tandem stated that the first use of the new tool will be to update t:slim pumps which were shipped prior to April, 2015 with a new version of the firmware which speeds the loading process and offers other enhancements. In late October 2016, Tandem began shipping its next-generation pump platform, the t:slim X2. The X2 will receive updates via the Tandem Product Updater product, with planned updates initially including integration with Dexcom's G5 and G6 Continuous Glucose Monitors, and eventually the integration of closed-loop technology which Tandem licensed from TypeZero in July 2016.