Yes, landlords in Maryland are able to enter an occupied unit without permission if they are not obliged to abide by any other lease-related entry provision. However, most landlords and tenants work out an entry policy that includes when the landlord may enter and how much notice they must provide prior to finalizing their lease agreement. Even with that kind of policy in place, a landlord in Maryland may still be able to enter without permission during an emergency.
The information for this answer was found on our Maryland Landlord Tenant Rights answers.