This page is an FAQ based on guidance from the Manual of Patent Examining Procedure. It is provided as guidance, with links to the ground truth sources. This is information only: it is not legal advice.
No, the time period for filing a foreign priority claim cannot be extended. As stated in MPEP 214.01: “This time period is not extendable.”
However, if you miss the deadline, there is a possibility to file a petition to accept an unintentionally delayed priority claim. The MPEP states: “If a claim for priority under 35 U.S.C. 119(a)-(d) or (f), 365(a) or (b), or 386(a) or (b) is presented after the time period set in 37 CFR 1.55, the claim may be accepted if it includes the required identification information and is accompanied by a grantable petition to accept the unintentionally delayed claim for priority.”
For more information on unintentionally delayed priority claims, refer to MPEP § 214.02.