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

INITIAL STATEMENT OF BENEFICIAL OWNERSHIP OF SECURITIES

Filed pursuant to Section 16(a) of the Securities Exchange Act of 1934, Section 17(a) of the Public Utility Holding Company Act of 1935 or Section 30(h) of the Investment Company Act of 1940
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(Print or Type Responses)
1. Name and Address of Reporting Person *
  WHALEN CHAD MICHAEL
 2. Date of Event Requiring Statement (Month/Day/Year)
07/09/2018		 3. Issuer Name and Ticker or Trading Symbol
F5 NETWORKS INC [FFIV]
(Last)
(First)
(Middle)
C/O F5 NETWORKS, INC., 401 ELLIOTT AVE. WEST		 4. Relationship of Reporting Person(s) to Issuer
(Check all applicable)
_____ Director _____ 10% Owner
__X__ Officer (give title below) _____ Other (specify below)
EVP, Worldwide Sales
 5. If Amendment, Date Original Filed(Month/Day/Year)
(Street)

SEATTLE, WA 98119		 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 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)

Reminder: Report on a separate line for each class of securities beneficially owned directly or indirectly. SEC 1473 (7-02)
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Table II - Derivative Securities Beneficially Owned (e.g., puts, calls, warrants, options, convertible securities)
1. Title of Derivative Security
(Instr. 4)		 2. Date Exercisable and Expiration Date
(Month/Day/Year)		 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
Restricted Stock Units (1)   (2)   (3) Common Stock 2,339 $ 0 D  
Restricted Stock Units (1)   (4)   (3) Common Stock 498 $ 0 D  

Reporting Owners

Reporting Owner Name / Address Relationships
Director 10% Owner Officer Other
WHALEN CHAD MICHAEL
C/O F5 NETWORKS, INC.
401 ELLIOTT AVE. WEST
SEATTLE, WA 98119		       EVP, Worldwide Sales  

Signatures

/s/ Scot F. Rogers by Power of Attorney 07/17/2018
**Signature of Reporting Person Date

Explanation of Responses:

* 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).
(1) Each Restricted Stock Unit represents a contingent right to receive one share of F5 Networks, Inc. Common Stock on the vest date.
(2) The service-based Restricted Stock Units (RSUs) outstanding under this 02/01/2017 grant vest as follows: 213 vest 08/01/2018, 212 vest 11/1/2018, 213 vest 2/1/2019, 212 vest 05/01/2019, 213 vest 08/01/2019, 213 vest 11/01/2019, 212 vest 02/01/2020, 213 vest 05/01/2020, 212 vest 08/01/2020, 213 vest 11/01/2020 and 213 vest 02/01/2021.
(3) If the reporting person continues to provide services to the Company through the vest date, the corresponding number of shares of Common Stock of F5 Networks, Inc. will be issued to the reporting person on the vest date.
(4) The service-based Restricted Stock Units (RSUs) outstanding under this 11/01/2017 grant vest as follows: 83 vest 08/01/2018, 83 vest 11/1/2018, 83 vest 2/1/2019, 83 vest 05/01/2019, 83 vest 08/01/2019, 83 vest 11/01/2019.

Note: File three copies of this Form, one of which must be manually signed. If space is insufficient, See Instruction 6 for procedure.

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