Determining brand name similarity is vital in areas of trademark registration and brand confusion. Students rated the orthographic (spelling) similarity of word pairs (Experiments 1, 2, and 4) and brand name pairs (Experiment 5). Similarity ratings were consistently higher when words shared beginnings rather than endings, whereas shared pronunciation of the stressed vowel had small and less consistent effects on ratings. In Experiment 3 a behavioral task confirmed the similarity of shared beginnings in lexical processing. Specifically, in a task requiring participants to decide whether 2 words presented in the clear (a probe and a later target) were the same or different, a masked prime word preceding the target shortened response latencies if it shared its initial 3 letters with the target. The ratings of students for word and brand name pairs were strongly predicted by metrics of orthographic similarity from the visual word identification literature based on the number of shared letters and their relative positions. The results indicate a potential use for orthographic metrics in brand name registration and trademark law.