Between Armenia and CIS countries, including Tajikistan, the terms of intergovernmental agreements set a visa-free regime. This means that citizens of Tajikistan have the right to enter Armenia without a visa.

In any case, you will need to have a valid foreign passport with you, which you will need to show at the border. According to the current legislation, foreigners for whom a visa-free regime is established have the right to stay in Armenia no more than 180 days, then a temporary residence permit is required.