Company: NNN
Filing Date: 2025-06-25
Form Type: 424B5
Source: 0001193125-25-146859
Chunk: 0

Company: NNN REIT, INC.
Filing Date: 2025-06-25
Form: 424B5
Chunk 0
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Filed Pursuant to Rule 424(b)(5)
Registration No. 333-273605 PROSPECTUS SUPPLEMENT (To Prospectus dated August 2, 2023) $500,000,000 4.600% Notes due 2031 We are offering $500,000,000 aggregate principal amount of 4.600% notes due 2031. The notes will have the following terms:

| • |     | There is no sinking fund for the notes. |

| • |     | The notes will be our senior unsecured obligations and will rank equally with all of our other senior indebtedness from                                                                                                                                   
 time to time outstanding. However, the notes will be effectively subordinated to our mortgage debt and other secured indebtedness (to the extent of the value of the assets securing such debt) and will be structurally subordinated to the indebtedness 
 and other liabilities of our subsidiaries (to the extent of the value of the assets of those subsidiaries), if any.                                                                                                                                       |

| • |     | The notes will be a new series of securities with no established trading market. The notes will not be listed on any 
 securities exchange or automated quotation system.                                                                   |

Investing in the notes involves risks. See “ Risk Factors” beginning on page S-4of this prospectus supplement, page 6 of the accompanying prospectus and page 9 of our Annual Report on Form 10-Kfor the fiscal year ended December 31, 2024, which is incorporated herein by reference.

|                                                 |     | Per Note |        |   |     | Total |             |
|:------------------------------------------------|:----|:---------|-------:|:--|:----|:------|------------:|
| Public Offering Price(1)                        |     |          | 99.182 | % |     | $     | 495,910,000 |
| Underwriting Discount                           |     |          |  0.600 | % |     | $     |   3,000,000 |
| Proceeds to NNN REIT, Inc. (before expenses)(1) |     |          | 98.582 | % |     | $     | 492,910,000 |

| (1) | Plus accrued interest, if any, from July 1, 2025 if settlement occurs after that date. |

Neither the Securities and Exchange Commission nor any state securities commission has approved or disapproved of these securities or determined if this prospectus supplement or