| one-piece_tan | tan tanlines | |
| on_flower | flower | |
| onigiri | food | |
| onigiri_hair_ornament | food-themed_hair_ornament hair_ornament | |
| onigiri_print | food_print | |
| onii-shota | age_difference | |
| oni_mask | mask | |
| on-model_vs_in_your_style_challenge | multiple_drawing_challenge | |
| on_motorcycle | motor_vehicle motorcycle | |
| on_railing | railing | |
| on_side | lying | |
| on_stomach | lying | |
| on_table | table | |
| on_truck | motor_vehicle truck | |
| on_van | motor_vehicle van | |
| ooarai_(emblem) | emblem | |
| oohirakeisuke | banned_artist | |
| ooi_(anime_swimsuit)_(kancolle) | character:ooi_(kancolle) | |
| ooi_(new_year)_(kancolle) | character:ooi_(kancolle) | |
| ooi_(valentine)_(kancolle) | character:ooi_(kancolle) | |
| oonusa | gohei | |
| oonyuudou | banned_artist | |
| oosawa | banned_artist | |
| ooshio_(saury_festival)_(kancolle) | character:ooshio_(kancolle) | |
| ooyodo_(new_year)_(kancolle) | character:ooyodo_(kancolle) | |
| ooyodo_(swimsuit)_(kancolle) | character:ooyodo_(kancolle) | |
| ooyodo_(valentine)_(kancolle) | character:ooyodo_(kancolle) | |
| opaque_glasses | glasses | |
| opaque_monocle | monocle | |
| open_bag | bag | |