The Finnish Border Guard (Finnish: Rajavartiolaitos; Swedish: Gränsbevakningsväsendet) is the agency responsible for enforcing the security of Finland's borders. It is a military organisation, subordinate to the Ministry of the Interior in administrative issues and to the President of Finland in issues pertaining to his authority as Commander-in-Chief (e.g. officer promotions). The agency has police and investigative powers in immigration matters and can independently investigate immigration violations. The Border Guard has search and rescue (SAR) duties, both maritime and inland. Missions inland are often carried out in co-operation with local fire and rescue departments or other authorities.

The Finnish Border Guard consists of 3,800 active duty personnel. Upon mobilization, it would be wholly or partly incorporated into the Finnish Defence Forces and its strength increased with reservists who have served their conscription in the branch. The mobilized strength of the Finnish Border Guard is 12,600 servicemen. The Finnish-Russian border is actively monitored. The western sea borders and the western and northern land borders to Sweden and Norway are free to cross under the Nordic passport union, the Border Guard does however maintain personnel in these regions owing to its SAR duties.

There is a separate Finnish Customs agency, and immigration is also handled by the Finnish police and the Finnish Directorate of Immigration. PTR (police, customs and border guard) co-operation is well-developed and allows the authorities to conduct each other's duties if necessary.