The Republic of Albania allows dual citizenship.
Citizenship is granted under the following conditions:
Anyone born to at least one parent who holds Albanian citizenship gains automatic Albanian citizenship themselves. Albanian citizenship is gained also for other reasons provided by law (Article 19 of the Albanian Constitution).
If you can provide proof that one of your grandparents is Albanian, you can reduce the residency requirement from 5 years to 3 years (I am still waiting to get an actual citation for this. If I can not find one I will remove).
To apply for naturalization, you must maintain permanent residence in Albania for at least 5 years (Law on Albanian Citizenship Article 9).
One year of legal residence in Albania is required in addition to being married for at least 3 years to an Albanian citizen in order to apply for citizenship through marriage (Law on Albanian Citizenship Article 10).
Exceptions & Irregularities
Under the “Law of Albanian Citizenship” dual citizenship is mentioned under Article 3; however, if you read further, Article 27 says that only one citizenship must be chosen by an individual. An article by the EUDO also mentions that dual citizenship is allowed.