Morocco declared 31 October a national holiday on Tuesday to mark the day the United Nations Security Council voted in favour of a resolution backing its plan for the disputed Western Sahara.
The holiday, dubbed "Unity Day", will celebrate Morocco's "national unity and territorial integrity", the palace said in a statement carried by the official MAP news agency.
Western Sahara is a vast mineral-rich former Spanish colony that is largely controlled by Morocco but has been claimed for decades by the pro-independence Polisario Front, which is supported by Algeria.
The Security Council had previously urged Morocco, the Polisario Front, Algeria and Mauritania to resume talks to reach a broad agreement.
But, at the initiative of US President Donald Trump's administration, the council resolution supported a plan, initially presented by Rabat in 2007, in which Western Sahara would enjoy autonomy under Morocco's sole sovereignty.