Under Maryland law, anyone under the age of 18 is a minor.  Anyone 18 years of age or older is an adult.  There are exceptions under certain State laws to this general definition of who is a minor, but none of these apply to the landlord-tenant relationship.  For a rental lease, a minor is anyone under the age of eighteen (18).  Read the law: MD Code, General Provisions

Can a minor sign a lease?

Anyone can sign a lease.  The question is whether the person can be held accountable to follow the requirements of the lease, such as paying rent.  A lease is a contract.  A minor is generally not bound by his or her contracts.  This means that, if a minor enters into a contract, the law will allow the minor to cancel, or “void” the contract.  The law gives the minor the power to choose whether s/he wants to honor the contract or avoid the obligation.

There is, however, an exception.  If a minor receives any of the “basic necessities of life” under a contract, s/he is obligated to pay for them at a reasonable price.  Lodging is considered a basic necessity (Corpus Juris Secundum, Infants, § 240).

If a tenant is a minor at the beginning of his or her tenancy and continues to live in the rented property after reaching age 18, s/he can then be held to the terms of the lease as an adult.  (See Maryland Law Encyclopedia, Infants and Minors, §§ 43 & 48).

How can a landlord protect him/herself if a minor wants to rent an apartment?

If a landlord is worried about renting to a minor, the landlord can ask the minor to find an adult to co-sign the lease.  If any problems occur, the landlord can look to the adult for the unpaid rent or other problems.