Is it a mortal sin to disrespect your parents?

As kids it's not a bigger mortal sin, but make sure you do not hurt your parents in the process.

ALSO,

in the Old Testament, a rebellious son was grounds for that son being stoned to death, so in God's view, disrespecting your parents is a pretty serious matter. Mortal sin though? The truth is, there is no true "mortal sin", except dying in a state of unbelief and not receiving Jesus Christ as your Saviour, all the other "sins" is small fry by comparison.

Answer

It is shameful, if not sinful, as it is for parents to disrespect, especially abuse, their children.