All [the] students should attend the class.

[JaneGothic]

Which sentence is correct?
All students should attend the class
 Or
All the students should attend the class

 

[emsr2d2]

Which sentence is correct?

1. All students should attend the class.
 Or
2. All the students should attend the class.

They're both grammatically correct, as is "All of the students should attend the class". However, depending on context, they don't necessarily mean the same thing.

Note my improvements to the layout of your text and to your title.