Statement of Changes in Beneficial Ownership (Form 4)

FORM 4 Check this box if no longer subject to Section 16. Form 4 or Form 5 obligations may continue. See Instruction 1(b). Check this box to indicate that a transaction was made pursuant to a contract, instruction or written plan that is intended to satisfy the affirmative defense conditions of Rule 10b5-1(c). See Instruction 10.

UNITED STATES SECURITIES AND EXCHANGE COMMISSION Washington, D.C. 20549 STATEMENT OF CHANGES IN BENEFICIAL OWNERSHIP OF SECURITIES Filed pursuant to Section 16(a) of the Securities Exchange Act of 1934 or Section 30(h) of the Investment Company Act of 1940

OMB APPROVAL OMB Number: 3235-0287 Estimated average burden hours per response... 0.5

(Print or Type Responses)

1. Name and Address of Reporting Person * Fernandez Gomez Luciano 2. Issuer Name and Ticker or Trading Symbol Klaviyo, Inc. [KVYO] 5. Relationship of Reporting Person(s) to Issuer (Check all applicable) __X__ Director _____ 10% Owner __X__ Officer (give title below) _____ Other (specify below) Co-Chief Executive Officer (Last) (First) (Middle) C/O KLAVIYO, INC. 125 SUMMER STREET, 6TH FLOOR 3. Date of Earliest Transaction (Month/Day/Year) 01/15/2026 (Street) BOSTON, MA 02110 4. If Amendment, Date Original Filed (Month/Day/Year) 6. Individual or Joint/Group Filing (Check Applicable Line) _X_ Form filed by One Reporting Person ___ Form filed by More than One Reporting Person (City) (State) (Zip) Table I - Non-Derivative Securities Acquired, Disposed of, or Beneficially Owned

1.Title of Security (Instr. 3) 2. Transaction Date (Month/Day/Year) 2A. Deemed Execution Date, if any (Month/Day/Year) 3. Transaction Code (Instr. 8) 4. Securities Acquired (A) or Disposed of (D) (Instr. 3, 4 and 5) 5. Amount of Securities Beneficially Owned Following Reported Transaction(s) (Instr. 3 and 4) 6. Ownership Form: Direct (D) or Indirect (I) (Instr. 4) 7. Nature of Indirect Beneficial Ownership (Instr. 4) Code V Amount (A) or (D) Price Series A Common Stock 01/15/2026 A 1,093,801(1) A $ 0 1,177,653 D Series A Common Stock 01/15/2026 A 1,193,238(2) A $ 0 2,370,891(3) D

Reminder: Report on a separate line for each class of securities beneficially owned directly or indirectly.
	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.		SEC 1474 (9-02)

Table II - Derivative Securities Acquired, Disposed of, or Beneficially Owned
(e.g., puts, calls, warrants, options, convertible securities)

1. Title of Derivative Security (Instr. 3)

2. Conversion or Exercise Price of Derivative Security

3. Transaction Date (Month/Day/Year)

3A. Deemed Execution Date, if any (Month/Day/Year)

4. Transaction Code (Instr. 8)

5. Number of Derivative Securities Acquired (A) or Disposed of (D) (Instr. 3, 4, and 5)

6. Date Exercisable and Expiration Date (Month/Day/Year)

7. Title and Amount of Underlying Securities (Instr. 3 and 4)

8. Price of Derivative Security (Instr. 5)

9. Number of Derivative Securities Beneficially Owned Following Reported Transaction(s) (Instr. 4)

10. Ownership Form of Derivative Security: Direct (D) or Indirect (I) (Instr. 4)

11. Nature of Indirect Beneficial Ownership (Instr. 4)

Code

V

(A)

(D)

Date Exercisable

Expiration Date

Title

Amount or Number of Shares

Reporting Owners

Reporting Owner Name / Address	Relationships
	Director	10% Owner	Officer	Other
Fernandez Gomez Luciano C/O KLAVIYO, INC. 125 SUMMER STREET 6TH FLOOR BOSTON, MA 02110	X		Co-Chief Executive Officer

Signatures

/s/ Landon Edmond, Attorney-in-Fact		01/16/2026
**Signature of Reporting Person		Date

Explanation of Responses:

*	If the form is filed by more than one reporting person, see Instruction 4(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).
(1)	Represents restricted stock units ("RSUs") awarded under the Issuer's 2023 Stock Option and Incentive Plan (the "Plan"), each representing the contingent right to receive one share of the Issuer's Series A Common Stock, par value $0.001 per share ("Series A Common Stock"), upon vesting and settlement. The RSUs will vest in twelve equal quarterly installments, with the first such installment vesting on February 15, 2026, subject to the Reporting Person's continued service as the Issuer's co-Chief Executive Officer on each such vesting date.
(2)	Represents performance stock units ("PSUs") awarded under the Plan, each representing the contingent right to receive one share of Series A Common Stock upon vesting and settlement. The PSUs will vest in up to four tranches over a five-year measurement period, subject to the achievement of specified performance targets tied to the trading price of the Series A Common Stock and the Reporting Person's continued service as the Issuer's co-Chief Executive Officer through the applicable vesting date. Each tranche of PSUs will vest only if the trading price of the Series A Common Stock closes at or above a specified dollar value for a period of at least sixty consecutive calendar days during the applicable measurement period. The stock price targets for tranches 1 through 4 are $40.00, $55.00, $70.00, and $85.00 per share, respectively, subject to proportionate adjustment in the event of any stock split or other similar change in the Issuer's capital stock.
(3)	Consists of (i) 78,032 shares of Series A Common Stock; (ii) 1,099,621 unvested RSUs awarded under the Plan, each representing the contingent right to receive one share of Series A Common Stock upon vesting and settlement; and (iii) 1,193,238 unvested PSUs awarded under the Plan, each representing the contingent right to receive one share of Series A Common Stock upon vesting and settlement.

Note: File three copies of this Form, one of which must be manually signed. If space is insufficient, see Instruction 6 for procedure. Potential persons who are to respond to the collection of information contained in this form are not required to respond unless the form displays a currently valid OMB number.