Conscription in Finland is part of a general compulsion for national military service for all adult males (Finnish: Asevelvollisuus; Swedish: Värnplikt) defined in the section 127 of the Constitution of Finland.

Conscription can take the form of military or of civilian service. According to Finnish Defence Forces 2011 data, slightly under 65% of Finnish males turned 30 had entered and finished the military service. The number of female volunteers to annually enter armed service had stabilized at approximately 300. The service period is 165 days, 255 days, or 347 days for the rank and file conscripts and 347 days for conscripts trained as non-commissioned officers or reserve officers. The length of civilian service is always twelve months. Those electing to serve unarmed in duties where unarmed service is possible serve either nine or twelve months, depending on their training.

Any Finnish citizen who refuses to perform both military and civilian service faces a penalty of 173 days in prison, minus any served days. Such sentences are usually served fully in prison, with no parole. Jehovah's Witnesses are no longer exempted from service as of February 27, 2019. The inhabitants of demilitarized Åland are exempt from military service. By the Conscription Act of 1951, they are, however, required to serve a time at a local institution, like the coast guard. However, until such service has been arranged, they are freed from service obligation. The non-military service of Åland islands has not been arranged since the introduction of the act, and there are no plans to institute it. The inhabitants of Åland islands can also volunteer for military service on the mainland. Dual nationals of Finland and another country can also be exempted if they either complete at least 4 months of military service in another country, or have resided overseas for at least 7 years and do not move back to Finland before the age of 29.

As of 1995, women are permitted to serve on a voluntary basis and pursue careers in the military after their initial voluntary military service.

The military service takes place in Finnish Defence Forces or in the Finnish Border Guard. All services of the Finnish Defence Forces train conscripts. However, the Border Guard trains conscripts only in land-based units, not in coast guard detachments or in the Border Guard Air Wing. Civilian service may take place in the Civilian Service Center in Lapinjärvi or in an accepted non-profit organization of educational, social or medical nature.

The Finnish Defence Forces are based on a universal male conscription. All men above 18 years of age are liable to serve either 165, 255 or 347 days. Yearly, about 27,000 conscripts are trained. About 80% of Finnish male citizens complete the service. Thus, Finland has one of the highest rates of conscription, along with such countries as Singapore, Israel, Armenia, South Korea, Turkey, Estonia, and North Korea. The conscripts first receive basic training (8 weeks), after which they are assigned to various units for special training. Privates who are trained for tasks not requiring special skills serve for five and a half months. In technically demanding tasks, the time of service is eight and a half months or (in some cases, such as those selected for NCO or officer training) eleven and a half months.

All males are liable to report at the drafting event (Finnish: kutsunnat, Swedish: uppbåd) of their municipality in the autumn of the year they turn 18. The Finnish Defence Forces sends the youth an official invitation to the event along with an information package. Prior to the drafting event, the male is required to visit a municipal doctor for a physical examination. The drafting event is held simultaneously for all males of the age cohort of the municipality. In cities where this would be unfeasible, the age cohort is divided to different days based on the first letters of surname. The drafting event consists of a number of lectures, after which a doctor appointed by the municipality gives each male a physical examination. After the check-up, the youth meets the draft board in person. The draft board consists of two officers from the military regional office and one civilian appointed by the municipality. The youth can express his wishes for a service location, branch of service and the time of induction. After this, the board decides whether the youth is fit for service. If he is not, he is exempted completely or temporarily. Those fit for service are given an order of induction that determines their place of service and time of induction, or if necessary, a letter of delayed service. It is also possible for the youth to elect national service in front of the draft board. The decision of the draft board to give an induction order or to give a declaration of unfitness for service can be appealed against to the Central Draft Board which has five legally trained members and two members who have a minimum rank of lieutenant colonel. The decision of the Central Draft Board is final.

The draft board uses a system of six grades (only five of which are in active use) to determine the draftee's fitness for duty: