Md. Code, Election Law § 3-102

(a) (1) Except as provided in subsection (b) of this section, an individual may become registered to vote if the individual:

(i) is a citizen of the United States;

(ii) is at least 16 years old;

(iii) is a resident of the State as of the day the individual seeks to register; and

(iv) registers pursuant to this title.

(2) Notwithstanding paragraph (1)(ii) of this subsection, an individual under the age of 18 years:

(i) may vote in a primary election in which candidates are nominated for a general or special election that will occur when the individual is at least 18 years old; and

(ii) may not vote in any other election.

(b) An individual is not qualified to be a registered voter if the individual:

(1) has been convicted of a felony and is currently serving a court–ordered sentence of imprisonment for the conviction;

(2) is under guardianship for mental disability and a court of competent jurisdiction has specifically found by clear and convincing evidence that the individual cannot communicate, with or without accommodations, a desire to participate in the voting process; or

(3) has been convicted of buying or selling votes.