| AUTHOR | SERIES/BOOK TITLE |
| O'Brien, Jack | BEST BOOK OF DOG STORIES |
| BIG BOOK OF FAVORITE DOG STORIES |
| O'Brien, William | JUMBO ELEPHANT PLANE |
| O'Donnell, Mabel | ALL THROUGH THE YEAR |
| ANYTHING CAN HAPPEN |
| AROUND THE CORNER |
| CITY DAYS, CITY WAYS |
| DAY IN AND DAY OUT |
| ENGINE WHISTLES |
| FIVE-AND-A-HALF CLUB |
| FROM CODES TO CAPTAINS |
| FROM FARAWAY PLACES |
| HAPPY DAYS |
| HIGH ON A HILL |
| JANET AND MARK |
| NEIGHBORS ON THE HILL |
| OPEN THE DOOR |
| REAL AND MAKE-BELIEVE |
| ROUND ABOUT |
| UNDER THE SKY |
| WISHING WELL |
| O'Donoghue, Maureen | WINNER |
| O'Farrell, Kathleen | GIRL'S CHOICE |
| O’Grady, Alice | THE THREE BILLY GOATS GRUFF |
| O’Hara, David | JIMMIE DRURY |
| O’Hara, Mary | BIG BOOK OF FAVORITE HORSE STORIES |
| MY FRIEND FLICKA |
| THUNDERHEAD |
| O'Meara, Walter | THE FIRST NORTHWEST PASSAGE |
| O'Reilly, Alice | CAP THAT MOTHER MADE, THE |
| O'Rourke, Frank | GROSSET & DUNLAP FAMOUS SPORTS STORIES |
| Ober, Frederick | THE NAVY BOYS |
| Obermeyer, Marion | YOUNG READERS ADVENTURE STORIES |
Oblinger, Milo Milton (writing as Milton Richards) | ADVENTURE & MYSTERY SERIES |
| BOYS OF THE ROYAL MOUNTED POLICE |
| DICK KENT |
| NORTHLAND SERIES |
| Ochocki, Phyllis | BETH'S HAPPY DAY |
| Offerman, Lynn | THE TRUCK THAT DROVE ALL NIGHT |
| Oftedal, Laura | MY FIRST DICTIONARY |
| Ogden, George W. | ROAD TO MONTEREY |
| Olcott, Virginia | WORLD'S CHILDREN SERIES |
| Old Sleuth | OLD ELECTRICITY |
| Olds, Helen Diehl | EVERYGIRLS CAREER STORIES |
| HEADLINE BOOKS FOR GIRLS |
| Olgin, Joseph | THE SCORING TWINS |
| Oliver, Mark | FLAMINGO |
| Ollivant, Alfred | THE BIG BOOK OF FAVORITE DOG STORIES |
| BOB, SON OF BATTLE |
| Olney, Ross R. (Editor) | SHUDDERS |
| TALES OF TIME & SPACE |
| Onstott, Kyle | CHILD OF THE SUN |
| FALCONHURST/MANDINGO SERIES |
| Optic, Oliver | BOAT CLUB SERIES |
| BOYS BANNER SERIES |
| OLIVER OPTIC BOOKS |
| OLIVER OPTIC SERIES |
| STARRY FLAG |
| UPWARD AND ONWARD SERIES |
| Orbaan, Albert |
FORKED LIGHTNING |
| Ormondroyd, Edward | DAVID AND THE PHOENIX |
| Ornish, Dean | EAT MORE, WEIGH LESS |
| Orr, Frank | THE STORY OF HOCKEY |
| WORLD'S GREAT RACE DRIVERS |
| Orton, George W. | BOB HUNT |
| Orton, James K. | FAMOUS ADVENTURE SERIES |
| Orwell, George | 1984 |
| Otis, James | ADMIRAL SPURWINK |
| CASTAWAYS, THE |
| CLUB AT CROW'S CORNER |
| MR. STUBBS'S BROTHER |
| NAVY BOYS |
| TELEGRAPH TOM |
| TOBY TYLER |
| TOM DEXTER GOES TO SCHOOL |
| WRECKED ON SPIDER ISLAND |
| YOUNG PATRIOTS |
| Ouida | A DOG OF FLANDERS |
| Osswald, Edith | NUMBERS |
| Oswald, Felix L. | ADVENTURES IN THE TROPICS |
| Ottum, Bob | MY LITTLE BOOK OF BIG MACHINES |
| Ouida | A DOG OF FLANDERS (Rand McNally Edition) |
| | A DOG OF FLANDERS (Saalfield Edition) |
| Ousley, Odille | AROUND THE CORNER |
| COME WITH US |
| FINDING NEW NEIGHBORS |
| LITTLE WHITE HOUSE, THE |
| MY LITTLE RED STORY BOOK |
| ON CHERRY STREET |
| RANCHES AND RAINBOWS |
| UNDER THE APPLE TREE |
| Overton, Mark | AMERICAN BOYS SPORTS SERIES |
| BOYS PRIZE LIBRARY |
| JACK WINTERS |
| Owen, Frank | TEEN-AGE BASEBALL STORIES |
| TEEN-AGE COMPANION |
| TEEN-AGE FOOTBALL STORIES |
| TEEN-AGE MYSTERY STORIES |
| TEEN-AGE OUTDOOR STORIES |
| TEEN-AGE SPORTS STORIES |
| TEEN-AGE STORIES OF ACTION |
| TEEN-AGE WINTER STORIES |
| Owens, Frank | TEEN-AGE COMPANION |
| TEEN-AGE FOOTBALL STORIES |
| TEEN-AGE OUTDOOR STORIES |
| TEEN-AGE SPORTS STORIES |
| TEEN-AGE STORIES OF ACTION |
| TEEN-AGE WINTER STORIES |
| Oxenham, Elsie J. | ABBEY SCHOOL |
| Ozone, Lucy | SURPRISE! |