Kiara Lee, 26, was taken into custody on Tuesday night.
Some Penn Wood Middle School students allegedly reported Lee would smoke marijuana with the kids.
Police say Lee was also contacting at least one student via text.
In those messages, police say, the student and Lee would talk about ingesting marijuana edibles and share their experiences.
"While marijuana may not seem like a big deal to some folks in the community, I think we can all agree that crossing guards should not be providing narcotics - even if it is 'just' marijuana - to our kids," Darby Borough Chief Joseph Gabe said in a statement.
Charges against Lee include possession of marijuana with intent to deliver and corruption of minors.
Anyone concerned about their child's interactions with Lee is asked to contact the Darby Borough Police Department at 610-586-1102.