Company: KELYB
Filing Date: 2025-05-19
Form Type: S-8
Source: 0001193125-25-122459
Chunk: 0

Company: KELLY SERVICES INC
Filing Date: 2025-05-19
Form: S-8
Chunk 0
---
As filed with the Securities and Exchange Commission on May 19, 2025 Registration No. 333- UNITED STATES SECURITIES AND EXCHANGE COMMISSION WASHINGTON, DC 20549 FORM S-8 REGISTRATION STATEMENT UNDER THE SECURITIES ACT OF 1933 KELLY SERVICES, INC. (Exact Name of Registrant as Specified in Its Charter)

| Delaware                                 |     |            38-1510762 |
| (State or Other Jurisdiction of          
 Incorporation or Organization)           |     |      -I.R.S. Employer 
 Identification Number |
| 999 West Big Beaver Road                 
 Troy, Michigan                           |     |                 48084 |
| (Address of Principal Executive Offices) |     |             -Zip Code |

Kelly Services, Inc. 2025 Equity Incentive Plan (Full Title of the Plan) Vanessa Peterson Williams Executive Vice President, General Counsel and Corporate Secretary Kelly Services, Inc. 999 West Big Beaver Road Troy, Michigan 48084 (Name and Address of Agent for Service) (248) 362-4444 (Telephone Number, Including Area Code, of Agent for Service) Indicate by check mark whether the registrant is a large accelerated filer, an accelerated filer, a non-acceleratedfiler, a smaller reporting company or an emerging growth company. See the definitions of “large accelerated filer,” “accelerated filer,” “smaller reporting company” and “emerging growth company” in Rule 12b-2of the Exchange Act.

| Large accelerated filer |     | ☐ |     | Accelerated filer         |     | ☒ |
| Non-accelerated filer   |     | ☐ |     | Smaller reporting company |     | ☐ |
|                         |     |   |     | Emerging growth company   |     | ☐ |

If an emerging growth company, indicate by check mark if the registrant has elected not to use the extended transition period for complying with any new or revised financial accounting standards provided pursuant to Section 7(a)(2)(B) of the Securities Act. ☐

PART I INFORMATION REQUIRED IN THE SECTION 10(a) PROSPECTUS The documents containing information specified by Part I of this Registration Statement on Form S-8(this “Registration Statement”) have been or will be sent or given to participants in the plan listed on the cover of this Registration Statement (the “Plan”) as specified in Rule 428(b)(1)