Build phonics skills and practice beginning sound O with your children! This worksheet features pictures of things that begin with the letter O. Teachers and parents can use this printable to introduce the concept of identifying words that start with the letter O. The beginning letter O is highlighted in red to show the vowel sound. Things that begin with the letter O: officer, ox, omelet, octopus, oak, oatmeal, open, ocean. Printing options: full color, color lines, and black lines.