Eighth-grade girls (N=257) randomly selected from nine different public junior high schools in central Texas were questioned in order to identify the communicators whom they perceive as highly credible regarding reasons for taking elective physical science courses in high school and the attributes associated with these communicators. Four persons were each identified by better than 10 percent of the sample as the best person to try to convince junior high school girls to take elective physical science courses in high school. In order of perceived credibility, these persons are “father,” “woman science teacher,” “mother,” and “boy high school student.” Slight variations in the order of perceived credibility were found when the responses from girls of the different ethnic groups represented in the sample (Caucasian, Hispanic, Black, and Asian) were examined separately. Attributes listed by the respondents for “father,” “woman science teacher,” “mother,” and “boy high school student” were examined and classified into the categories of prestige, trustworthiness, similarity, attractiveness, and power. Prestige and trustworthiness are the attributes associates most frequently with communicators identified as highly credible. Implications of the present study and suggestions for further research are discussed.