The U.S. National Science Foundation (NSF) SBIR/STTR program has extended the solicitation window closing date for both SBIR/STTR Phase I (NSF 23-515) and Phase II (NSF 23-516) solicitations from November 1, 2023 to January 9, 2024 at 5:00 PM submitter’s local time.

NSF SBIR/STTR Phase I and Phase II applicants will still need to submit their proposals according to the eligibility criteria outlined in the NSF SBIR/STTR Phase I and Phase II solicitations.

If you were planning to submit your Phase I or Phase II proposal on November 1, 2023, you are still welcome to do so, and we will do our best to ensure November submissions are reviewed as soon as possible after submission. 

Note: Project Pitch Submission windows are unchanged, we are not giving extensions to Phase I Project Pitch invitations or Phase II submission deadlines. For example, if your Phase I Project Pitch invitation or Phase II submission deadline has an expiration date of November 20, 2023, you should plan to submit your full proposal on or before November 20, 2023, regardless of the window extension.

Stay tuned for new SBIR/STTR Phase I and Phase II submission opportunities.


  • For NSF technical questions or immediate assistance, please contact the NSF IT Service Desk (7:00 AM – 9:00 PM Eastern Time, Monday through Friday except for federal holidays):
    Email the NSF IT Service
    Call the NSF IT Service Desk1-800-381-1532
  • SBIR/STTR program-related questions should be directed to