FORM 3
        	UNITED STATES SECURITIES AND EXCHANGE COMMISSION
Washington, D.C. 20549

INITIAL STATEMENT OF BENEFICIAL OWNERSHIP OF SECURITIES
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                      	Filed pursuant to Section 16(a) of the Securities Exchange Act of 1934 or Section 30(h) of the Investment Company Act of 1940	                      	

1. Name and Address of Reporting Person *

Charles River XIII GP, LLC	2. Date of Event Requiring Statement (MM/DD/YYYY)
5/14/2014 
	3. Issuer Name and Ticker or Trading Symbol

Zendesk, Inc. [ZEN]	
(Last)        (First)        (Middle)

ONE BROADWAY, 15TH FLOOR	4. Relationship of Reporting Person(s) to Issuer (Check all applicable)

_____ Director                            ___ X ___ 10% Owner
_____ Officer (give title below)          _____ Other (specify below)	
(Street)

CAMBRIDGE, MA 02142       

(City)              (State)              (Zip)	5. If Amendment, Date Original Filed (MM/DD/YYYY)

5/14/2014 
	6. Individual or Joint/Group Filing (Check Applicable Line)

___ Form filed by One Reporting Person
_ X _ Form filed by More than One Reporting Person	

Table I - Non-Derivative Securities Beneficially Owned	
1.Title of Security
(Instr. 4)	2. Amount of Securities Beneficially Owned
(Instr. 4)	3. Ownership Form: Direct (D) or Indirect (I)
(Instr. 5)	4. Nature of Indirect Beneficial Ownership
(Instr. 5)	

Table II - Derivative Securities Beneficially Owned ( e.g. , puts, calls, warrants, options, convertible securities)	
1. Title of Derivate Security
(Instr. 4)	2. Date Exercisable and Expiration Date
(MM/DD/YYYY)	3. Title and Amount of Securities Underlying Derivative Security
(Instr. 4)	4. Conversion or Exercise Price of Derivative Security	5. Ownership Form of Derivative Security: Direct (D) or Indirect (I)
(Instr. 5)	6. Nature of Indirect Beneficial Ownership
(Instr. 5)	
	Date Exercisable	Expiration Date	Title	Amount or Number of Shares				
Series B Common Stock  	  (1)	  (1)	Series A Common Stock  	3844  	  (1)	I  	By Charles River Friends XIII-A, LP   (2)	
Series B Common Stock  	  (1)	  (1)	Series A Common Stock  	136975  	  (1)	I  	By Charles River Partnership XIII, LP   (3)	
Series A Preferred Stock  	  (4)	  (4)	Series A Common Stock  	244496  	  (4)	I  	By Charles River Friends XIII-A, LP   (2)	
Series A Preferred Stock  	  (4)	  (4)	Series A Common Stock  	8710822  	  (4)	I  	By Charles River Partnership XIII, LP   (3)	
Series B Preferred Stock  	  (4)	  (4)	Series A Common Stock  	104542  	  (4)	I  	By Charles River Friends XIII-A, LP   (2)	
Series B Preferred Stock  	  (4)	  (4)	Series A Common Stock  	3724628  	  (4)	I  	By Charles River Partnership XIII, LP   (3)	
Series C Preferred Stock  	  (4)	  (4)	Series A Common Stock  	27406  	  (4)	I  	By Charles River Friends XIII-A, LP   (2)	
Series C Preferred Stock  	  (4)	  (4)	Series A Common Stock  	976404  	  (4)	I  	By Charles River Partnership XIII, LP   (3)	
Series D Preferred Stock  	  (4)	  (4)	Series A Common Stock  	4135  	  (4)	I  	By Charles River Friends XIII-A, LP   (2)	
Series D Preferred Stock  	  (4)	  (4)	Series A Common Stock  	147312  	  (4)	I  	By Charles River Partnership XIII, LP   (3)	

Explanation of Responses:	
(  1) 	Each share of Series B Common Stock automatically converts into Series A Common Stock on a 1-for-1 basis immediately prior to the closing of the Issuer's initial public offering of Common Stock and has no expiration date nor conversion price.	
(  2) 	Consists of shares held by Charles River Friends XIII-A, LP. Charles River XIII GP, LLC is the ultimate general partner of Charles River Friends XIII-A, LP and may be deemed to hold voting and dispositive power with respect to the reported securities but disclaims beneficial ownership except to the extent of its pecuniary interest therein. The filing of this statement by any reporting person shall not be deemed an admission that such person is, for purposes of Section 16 of the Securities Exchange Act of 1934 or otherwise, the beneficial owner of any equity securities covered by this statement.	
(  3) 	Consists of shares held by Charles River Partnership XIII, LP. Charles River XIII GP, LLC is the ultimate general partner of Charles River Partnership XIII, LP and may be deemed to hold voting and dispositive power with respect to the reported securities but disclaims beneficial ownership except to the extent of its pecuniary interest therein. The filing of this statement by any reporting person shall not be deemed an admission that such person is, for purposes of Section 16 of the Securities Exchange Act of 1934 or otherwise, the beneficial owner of any equity securities covered by this statement.	
(  4) 	Each share of Series A Preferred Stock, Series B Preferred Stock, Series C Preferred Stock and Series D Preferred Stock automatically converts into Series A Common Stock on a 1-for-1 basis immediately prior to the closing of the Issuer's initial public offering of Common Stock and has no expiration date nor conversion price.	

Reporting Owners	
Reporting Owner Name / Address	Relationships	
	Director	10% Owner	Officer	Other	
Charles River XIII GP, LLC
ONE BROADWAY, 15TH FLOOR
CAMBRIDGE, MA 02142		X			
Charles River Friends XIII-A LP
ONE BROADWAY, 15TH FLOOR
CAMBRIDGE, MA 02142		X			
Charles River Partnership XIII, LP
ONE BROADWAY, 15TH FLOOR
CAMBRIDGE, MA 02142		X			

Signatures		
Charles River XIII GP, LLC By: Charles River XIII GP, LLC Its: General Partner /s/ Devdutt Yellurkar, Authorized Manager		5/23/2014	
** Signature of Reporting Person		Date
	
Charles River Friends XIII-A, LP, By: Charles River XIII GP, LP, Its: General Partner, By: Charles River XIII GP, LLC, Its: General Partner /s/ John Geschke as Attorney in fact		5/14/2014	
** Signature of Reporting Person		Date
	
Charles River Partnership XIII, LP, By: Charles River XIII GP, LLC, Its: General Partner /s/ John Geschke as Attorney in fact		5/14/2014	
** Signature of Reporting Person		Date

Reminder: Report on a separate line for each class of securities beneficially owned directly or indirectly.	
*	If the form is filed by more than one reporting person, see Instruction 5(b)(v).	
**	Intentional misstatements or omissions of facts constitute Federal Criminal Violations. See 18 U.S.C. 1001 and 15 U.S.C. 78ff(a).	
Note:	File three copies of this Form, one of which must be manually signed. If space is insufficient, see Instruction 6 for procedure.	
Persons who respond to the collection of information contained in this form are not required to respond unless the form displays a currently valid OMB control number.	

LIMITED POWER OF ATTORNEY
The undersigned hereby constitutes and appoints each of Mikkel Svane, Alan Black, John Geschke, William J. Schnoor Jr., and Bradley C. Weber, signing singly, and with full power of substitution, the undersigned's true and lawful attorney-in-fact to:
(1) execute for and on behalf of the undersigned, in the undersigned's capacity as a Section 16 reporting person of Zendesk, Inc. (the "Company"), from time to time the following U.S. Securities and Exchange Commission ("SEC") forms: (i) Form ID, including any attached documents, to effect the assignment of codes to the undersigned to be used in the transmission of information to the SEC using the EDGAR System; (ii) Form 3, Initial Statement of Beneficial Ownership of Securities, including any attached documents; (iii) Form 4, Statement of Changes in Beneficial Ownership of Securities, including any attached documents;
(iv) Form 5, Annual Statement of Beneficial Ownership of Securities in accordance with Section 16(a) of the Securities Exchange Act of 1934, as amended, and the rules thereunder, including any attached documents; (v) Schedule 13D and (vi) amendments of each thereof, in accordance with the Securities Exchange Act of 1934, as amended, and the rules thereunder, including any attached documents;
(2) do and perform any and all acts for and on behalf of the undersigned which may be necessary or desirable to complete and execute any such Form 3, 4 or 5, Schedule 13D or any amendment(s) thereto, and timely file such form(s) with the SEC and any securities exchange, national association or similar authority; and
(3) take any other action of any type whatsoever in connection with the foregoing which, in the opinion of such attorney-in-fact, may be of benefit to, in the best interest of, or legally required by, the undersigned, it being understood that the documents executed by such attorney-in-fact on behalf of the undersigned pursuant to this Power of Attorney shall be in such form and shall contain such terms and conditions as such attorney-in-fact may approve in such attorney-in-fact's discretion.
The undersigned hereby grants to each such attorney-in-fact, acting singly, full power and authority to do and perform any and every act and thing whatsoever requisite, necessary or proper to be done in the exercise of any of the rights and powers herein granted, as fully to all intents and purposes as the undersigned might or could do if personally present, with full power of substitution or revocation, hereby ratifying and confirming all that such attorney-in-fact, or such attorney-in-fact's substitute or substitutes, shall lawfully do or cause to be done by virtue of this power of attorney and the rights and powers herein granted. The undersigned acknowledges that the foregoing attorneys-in-fact, in serving in such capacity at the request of the undersigned, are not assuming, nor is the Company assuming, any of the undersigned's responsibilities to comply with Section 16 or Regulation 13D-G of the Securities Exchange Act of 1934, as amended. The undersigned hereby agrees to indemnify the attorney in fact and the Company from and against any demand, damage, loss, cost or expense arising from any false or misleading information provided by the undersigned to the attorney-in fact.
This Power of Attorney shall remain in full force and effect until the undersigned is no longer required to file such forms with respect to the undersigned's holdings of and transactions in securities issued by the Company, unless earlier revoked by the undersigned in a signed writing delivered to the foregoing attorneys-in-fact.
IN WITNESS WHEREOF, the undersigned has caused this Power of Attorney to be executed as of April 29, 2014.
Charles River Friends XIII-A, LP
By: Charles River XIII GP, LP
Its: General Partner
By: Charles River XIII GP, LLC
Its: General Partner

/s/ Devdutt Yellurkar
Authorized Manager

Charles River Partnership XIII, LP
By: Charles River XIII GP, LLC
Its: General Partner

/s/ Devdutt Yellurkar
Authorized Manager

Charles River XIII GP, LLC
By: Charles River XIII GP, LLC
Its: General Partner

/s/ Devdutt Yellurkar
Authorized Manager