UNITED STATES

SECURITIES AND EXCHANGE COMMISSION

Washington, D.C. 20549

FORM 8-K

CURRENT REPORT

Pursuant to Section 13 or 15(d)

of The Securities Exchange Act of 1934

Date of Report (Date of earliest event reported): August 25, 2017

Tandem Diabetes Care, Inc.

(Exact name of registrant as specified in its charter)

Registrant’s telephone number, including area code: (858) 366-6900

N/A

(Former name or former address, if changed since last report)

Check the appropriate box below if the Form 8-K filing is intended to simultaneously satisfy the filing obligation of the registrant under any of the following provisions:

Indicate by check mark whether the registrant is an emerging growth company as defined in Rule 405 of the Securities Act of 1933 (§230.405 of this chapter) or Rule 12b-2 of the Securities Exchange Act of 1934 (§240.12b-2 of this chapter).

                                                                                                                                             Emerging growth company   ☒                                         

If an emerging growth company, indicate by check mark if the registrant has elected not to use the extended transition period for complying with any new or revised financial accounting standards provided pursuant to Section 13(a) of the Exchange Act.   ☒    

Item 8.01 Other Events

On August 25, 2017, the U.S. Food and Drug Administration (FDA) approved our pre-market application (PMA) for the t:slim X2 Insulin Pump with Dexcom G5^® Mobile continuous glucose monitoring (CGM) integration. The software featured on this newly approved pump will also be offered to current t:slim X2 Pump users at no cost via remote software update, allowing them to add CGM integration to their existing t:slim X2 Pumps from home using a personal computer. The t:slim X2 Pump with Dexcom G5 Mobile CGM integration is intended for the subcutaneous delivery of insulin, at set and variable rates, for the management of diabetes mellitus in persons requiring insulin for individuals 6 years of age and greater.

On August 28, 2017 we issued a press release announcing the FDA approval and commercial launch of the t:slim X2 Insulin Pump with Dexcom G5 Mobile integration. The accompanying press release is attached hereto as Exhibit 99.1 and is being furnished and shall not be deemed “filed” for the purposes of Section 18 of the Securities and Exchange Act of 1934, as amended, or the Exchange Act, or otherwise subject to the liabilities of that section, nor shall it be deemed incorporated by reference into any filing under the Securities Act of 1933, as amended, or the Exchange Act, except as expressly set forth by specific reference in such filing.

Item 9.01 Financial Statements and Exhibits.

(d) Exhibits.

SIGNATURES

Pursuant to the requirements of the Securities Exchange Act of 1934, the registrant has duly caused this report to be signed on its behalf by the undersigned hereunto duly authorized.

INDEX TO EXHIBITS