I really wanted to play this song around Christmas time, but I couldn't find any 
chords on here, so I decided to make a chart myself! I think it's 100% correct. Enjoy!

Intro: C - C#dim - G/D - E7 - A7 - D7 - G

    G                              D7                G
I think I saw ol' Santa through my window Christmas eve
    G                              D7         G
My eyes were really droopy but I really do believe
    Em               Bm            Em              E7
It must've been ol' Santa 'cause I saw his big red hat
       Am              D7                 G    F7  E7
And I know my mom and dad can't fly like that, Oh  no,
   Am             D7                  G         C - C#dim - G/D
I know my mom and dad can't fly like that.

     G                                  D7              G
And then I heard some footsteps in the hall outside my door
     G                                    D7                G
The same ol' Christmas trick my dad had played since I was four
     Em                Bm             Em             E7
He stands outside my bedroom yelling "Ho! Ho! Ho!" because
    Am              D7              G    F7  E7
He knows I don't believe in Santa Claus, no  way,
    Am             D7               G          C - C#dim - G/D
He knows I don't believe in Santa Claus.

   Eb             Bb                      Eb
I think my daddy sees me peeking from my door
    Fm    Gm         Bb/Ab  Bb  Eb
But he pretends he's Santa  anyway
      Eb                Bb                       Eb
Every year he tries to fool me but I'm a big boy now 
   Fm               Bb            Eb         D7
I don't believe in Santa or his sleigh... No way!

      G                         D7                 G
So I went back to my bed and I curled up nice and tight
     G                            D7              G
I stared out of my window and I looked into the night
          Em         Bm                Em            E7
And then, all of a sudden, through my window I could see
       Am             D7      G  F7     E7      Am7 - D7 - G
Santa Claus was flying by and smiling at me    


[Chorus]
  C            G
Santa Claus, Santa Claus
    D7                G
It must've been ol' Santa Claus
  C            G
Santa Claus, Santa Claus
       D7              G
Happy "Ho! Ho! Ho!" to you

         G                       D7             G
Then I heard ol' Rudolph tellin' me to come outside
     G                           D7            G
He told me that ol' Santa wanted me to take a ride
     Em              Bm            Em              E7
I climbed out of my window and I jumped onto his sleigh
     Am             D7     G  F7   E7
And then ol' Santa took me up and away,
 Am           D7         G
Santa took me up up and away

    G                                  D7           G
We flew high above the rooftops of my sleepy town below
   G                                   D7                  G
I saw my big red school house and the town square picture show
        Em              Bm        Em            
It was really past my bedtime and so ol' Santa said
 Am                                           C - C#dim - G/D
"Little boys like you should be in bed"


      Eb               Bb
So I hollered "Ho! Ho! Ho!"
                     Eb
And I put on Santa's hat
 Fm     Gm     Bb/Ab     Bb      Eb
Then he let me hold the reins a while
    Eb              Bb                             Eb
We pulled up to my window and I jumped back in my room
       Fm               Bb          Eb - D7
And I waved goodbye to Santa with a smile


     G                                 D7                 G
When I woke up Christmas morning, well it was clear and bright
     G                               D7          G
My parents said my window had blown open in the night
    Em         Bm                Em              E7
I smiled as I told them that it must've been the cat
     Am                    D7             G    F7   E7
And they asked me where I got my big red hat, Yeah yeah!
      Am              D7              G
They asked me where I got my big red hat.


[Chorus]
  C            G
Santa Claus, Santa Claus
    D7                G
It must've been ol' Santa Claus
  C            G
Santa Claus, Santa Claus
       D7              G
Happy "Ho! Ho! Ho!" to you

      D7              G
Happy Ho! Ho! Ho! to you! (18x)