United States securities and exchange commission logo

                             July 13, 2022

       Stephen A. Vintz
       Chief Financial Officer
       Tenable Holdings, Inc.
       6100 Merriweather Drive
       Columbia, MD 21044

                                                        Re: Tenable Holdings,
                                                            Form 10-K for the
Year Ended December 31, 2021
                                                            Filed February 25,
                                                            Form 8-K furnished
April 26, 2022
                                                            File No. 001-38600

       Dear Mr. Vintz:

              We have limited our review of your filings to the financial
statements and related
       disclosures and have the following comments. In some of our comments, we
may ask you to
       provide us with information so we may better understand your disclosure.

              Please respond to these comments within ten business days by
providing the requested
       information or advise us as soon as possible when you will respond. If
you do not believe our
       comments apply to your facts and circumstances, please tell us why in
your response.

                                                        After reviewing your
response to these comments, we may have additional comments.

       Form 10-K for year ended December 31, 2021

       Management's Discussion and Analysis of Financial Condition and Results
of Operations
       Overview, page 44

   1.                                                   We note your disclosure
regarding recurring revenues. Please tell us, and in future filings
                                                        disclose, whether you
include subscription software license revenues that are recognized
                                                        upon delivery within
your measure of recurring revenue. Also, tell us the amount of such
                                                        subscription software
revenues recognized for each period presented.
 Stephen A. Vintz
FirstName  LastNameStephen A. Vintz
Tenable Holdings, Inc.
July       NameTenable Holdings, Inc.
     13, 2022
July 13,
Page  2 2022 Page 2
FirstName LastName
Factors Affecting Our Performance, page 45

2.       We note that evaluate your ability to expand sales with existing
customers by assessing
         your dollar-based net expansion rate on a last twelve months basis and
that such
         rate exceeded 110% for fiscal 2021. Please tell us, and in future
filings disclose, the
         specific percentage of the dollar-based net expansion rate for each
period presented. Also,
         tell us and disclose whether software license revenues, which are
recognized upon
         delivery and included within subscription revenues, are included in
the calculation of
         annual recurring revenue (ARR). Lastly, tell us and disclose the
percentage of ARR
         related to multi-year sales for each period presented to provide
further context to your
         disclosure of the alternative dollar-based net expansion rate. Refer
to Item 303(a) of
         Regulation S-K and SEC Release No. 33-10751.
Key Operating and Financial Metrics
Free Cash Flow and Unlevered Free Cash Flow, page 48

3.       We note that your non-GAAP liquidity measure of unlevered free cash
flow includes an
         adjustment for cash interest paid. Please revise to remove this
adjustment as charges that
         require cash settlement cannot be excluded from a non-GAAP liquidity
measure in a filed
         document. Refer to Item 10(e)(1)(ii)(A) of Regulation S-K.
Results of Operations, page 55

4.       Please tell us and in future filings revise to include a discussion
regarding the various
         factors that contributed to your revenue growth. At a minimum, address
in quantified
         terms the increase in revenue from new versus existing customers.
Refer to Item 303(a)
         of Regulation S-K.
5.       We note your discussion of interest (expense) income, net and
(benefit) provision for
         income taxes on pages 53 and 54 qualitatively discuss multiple factors
that impacted these
         line items, however, you do not include a further discussion of such
changes within
         Results of Operations. In future filings, when there are material
changes to a line item,
         please describe the underlying reasons for such changes in both
quantitative and
         qualitative terms, including the impact of offsetting factors. Refer
to Item 303(b) of
         Regulation S-K.
Form 8-K furnished April 26, 2022

Exhibit 99.1
Non-GAAP Financial Measures and Other Key Metrics, page 3

6.       You state that you believe your non-GAAP measure of unlevered free
cash flow is useful
         as a liquidity measure since it measures the cash that is available to
invest in your business
         and meet your current and future financing needs. To the extent you
continue to provide
         this measure in any future filings furnished with the Commission,
please revise to avoid
 Stephen A. Vintz
Tenable Holdings, Inc.
July 13, 2022
Page 3
         implying that such measure represents the residual cash flow available
for discretionary
         expenditures, since there are non-discretionary expenditures that are
not deducted from
         the measure. Refer to Question 102.07 of the Non-GAAP Compliance and
       In closing, we remind you that the company and its management are
responsible for the
accuracy and adequacy of their disclosures, notwithstanding any review,
comments, action or
absence of action by the staff.

       You may contact Joyce Sweeney, Senior Staff Accountant, at (202)
551-3449 or
Kathleen Collins, Accounting Branch Chief, at (202) 551-3499 with any

FirstName LastNameStephen A. Vintz                            Sincerely,
Comapany NameTenable Holdings, Inc.
                                                              Division of
Corporation Finance
July 13, 2022 Page 3                                          Office of
FirstName LastName