Mommy told me something a little girl should know.
It's all about the devil and I've learned to hate him so.
She said he causes trouble when you let him in the room.
He will never ever leave you if your heart is filled with gloom.

Chorus:
So let the sun shine in, face it with a grin.
Smilers never lose and frowners never win.
So let the sun shine in, face it with a grin
Open up your heart and let the sun shine in.

When you are unhappy, the devil wears a grin
But oh, he starts to running when the light comes pouring in
I know he'll be unhappy 'cause I'll never wear a frown
Maybe if we keep on smiling he'll get tired of hanging 'round. (Chorus)

If I forget to say my prayers the devil wears a grin.
But he feels so awful awful when he sees me on my knees
So if you're full of trouble and you never seem to win,
Just open up your heart and let the sun shine in. (Chorus)