The Terps had eight penalties for 70 yards in the first half.
Quarterback Josh Jackson went 10-for-21 and threw two interceptions.
Friday's game is this university's first sellout football game since 2015.
More than 50,000 fans are expected to come out for the Penn State football game on Sept. 27.
After taking the first game Saturday, Maryland struggled on the mound in game two.
After five errors combined Saturday, the Terps had none in their win Sunday.
The Nittany Lions outscored the Terps 21-4 on the day.