UNITED STATES

SECURITIES AND EXCHANGE COMMISSION

Washington, D.C. 20549





FORM 10-K/A

(Amendment No. 1)





(Mark One)

|☒ | ANNUAL REPORT PURSUANT TO SECTION 13 OR 15(d) OF THE SECURITIES EXCHANGE ACT OF 1934
|- | ------------------------------------------------------------------------------------

For the fiscal year ended December 31, 2017

OR



|☐ | TRANSITION REPORT PURSUANT TO SECTION 13 OR 15(d) OF THE SECURITIES EXCHANGE ACT OF 1934 FOR THE TRANSITION PERIOD FROM              TO
|- | ---------------------------------------------------------------------------------------------------------------------------------------

Commission File Number 001-38359





resTORbio,
Inc.

(Exact name of Registrant as specified in its Charter)







|                                                               |  |                                     
|-------------------------------------------------------------- |  | ------------------------------------
|Delaware                                                       |  | 81-3305277                          
|(State or other jurisdiction of
incorporation or organization) |  | (I.R.S. Employer
Identification No.)

500 Boylston Street, 12th Floor

Boston, MA 02116

(857) 315-5521

(Address, including zip code, and telephone number, including area code, of
registrants principal executive offices)

Securities registered pursuant to Section 12(b) of the Act:



|                                          |  |                                          
|----------------------------------------- |  | -----------------------------------------
|Title of each
class                       |  | Name of each exchange on
which registered
|Common Stock, par value $0.0001 per share |  | Nasdaq Global Select Market              

Securities registered pursuant to Section 12(g) of the Act:

None





Indicate by check mark if the
registrant is a well-known seasoned issuer, as defined in Rule 405 of the Securities Act.    ☐  Yes    ☒  No

Indicate by check mark if the registrant is not required to file reports pursuant to Section 13 or 15(d) of the
Act.    ☐  Yes    ☒  No

Indicate by check mark whether the registrant
(1) has filed all reports required to be filed by Section 13 or 15(d) of the Securities Exchange Act of 1934 during the preceding 12 months (or for such shorter period that the registrant was required to file such reports), and
(2) has been subject to such filing requirements for the past 90 days.    ☐  Yes    ☒  No

Indicate by check mark whether the registrant has submitted electronically and posted on its corporate Web site, if any, every Interactive Data File required
to be submitted and posted pursuant to Rule 405 of Regulation S-T during the preceding 12 months (or for such shorter period that the registrant was required to submit and post such
files).    ☒  Yes    ☐  No

Indicate by check mark if disclosure of delinquent
filers pursuant to Item 405 of Regulation S-K is not contained herein, and will not be contained, to the best of registrants knowledge, in definitive proxy or information statements incorporated by
reference in Part III of this Form 10-K or any amendment to this Form 10-K.  ☒

Indicate by check mark whether the registrant is a large accelerated filer, an accelerated filer, a non-accelerated
filer, smaller reporting company, or an emerging growth company. See the definitions of large accelerated filer, accelerated filer, smaller reporting company, and emerging growth company in Rule 12b-2 of the Exchange Act.



|                          |  |   |  |                         |  |   |  |                       |  |   |  |                                              
|------------------------- |  | - |  | ----------------------- |  | - |  | --------------------- |  | - |  | ---------------------------------------------
|Large accelerated filer   |  | ☐ |  | Accelerated filer       |  | ☐ |  | Non-accelerated filer |  | ☒ |  | (Do not check if a smaller reporting company)
|Smaller reporting company |  | ☐ |  | 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 7(a)(2)(B) of the Securities Act.  ☐

Indicate by check mark whether the registrant is a shell company (as defined in Rule 12b-2 of the Exchange
Act.):    ☐  Yes    ☒  No

The registrants common stock began trading on The
Nasdaq Global Select Market on January 26, 2018. As of March 23, 2018, the aggregate market value of the registrants voting and non-voting common stock held by
non-affiliates (without admitting that any person whose shares are not included in such calculation is an affiliate) computed by reference to the price at which the common stock was last sold on March 23,
2018 was approximately $113.6 million. The registrant has provided this information as of March 23, 2018 because the registrant was not a public company as of the last business day of its most recently completed second fiscal quarter and
therefore cannot calculate the aggregate market value of its voting and non-voting equity held by non-affiliates as of such date.

As of March 23, 2018 there were 28,046,315 shares of common stock, $0.0001 par value per share, outstanding.









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EXPLANATORY NOTE

This Amendment No. 1 to Form 10-K/A (this Amendment) amends the Annual Report on Form 10-K of resTORbio, Inc. (the Company) for the year ended December 31, 2017, originally filed with the Securities and Exchange Commission on March 29, 2018 (the Original Filing).
This Amendment is being filed solely to include revised Exhibits 31.1 and 31.2, which replace the previously filed versions of those exhibits, to include certain statements required by Item 601(b)(31) of
Regulation S-K inadvertently omitted when previously filed.

Except as described as above, no changes have
been made to the Original Filing. The Original Filing continues to speak as of the date of the Original Filing, and the Company has not updated the disclosures contained therein to reflect any events that have occurred as of a date subsequent to the
date of the Original Filing. Accordingly, this Amendment should be read in conjunction with the Original Filing and the Companys filings made with the SEC subsequent to the filing of the Original Filing. The filing of this Amendment is
not an admission that the Original Filing, when filed, included any untrue statement of a material fact or omitted to state a material fact necessary to make a statement not misleading.



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PART IV



|Item 15. | Exhibits, Financial Statement Schedules
|-------- | ---------------------------------------

The following documents are filed as exhibits to this
Amendment:



|           |  |                                                                                                                                               
|---------- |  | ----------------------------------------------------------------------------------------------------------------------------------------------
|ExhibitNo. |  | Description of Exhibit                                                                                                                        
|           | 
|31.1*      |  | Certification of Principal Executive Officer pursuant to Rule 
13a-14(a) or Rule 15d-14(a) of the Securities Exchange Act of 1934, as amended.
|           | 
|31.2*      |  | Certification of Principal Financial Officer pursuant to Rule 
13a-14(a) or Rule 15d-14(a) of the Securities Exchange Act of 1934, as amended.



|* | Filed herewith.
|- | ---------------

SIGNATURES

Pursuant to the requirements of Section 13 or 15(d) of the Securities Exchange Act of 1934, as amended, the Registrant has duly caused this report to be
signed on its behalf by the undersigned, thereunto duly authorized.



RESTORBIO, INC.By:

/s/ Chen SchorChen Schor
President and Chief Executive Officer
(Principal Executive Officer)


Date: April 27, 2018