This article compares public attitudes toward the use of prescription drugs for cognitive enhancement with the use of performance enhancing drugs in sport. We explore attitudes toward the acceptability of both practices; the extent to which familiarity with cognitive enhancement is related to its perceived acceptability; and relationships between the acceptability of cognitive enhancement and legalized doping in sport. A survey was administered through a computer-assisted telephone interviewing system to members of the Australian general public aged 18–101 years in the state of Queensland. Of 1,265 participants, 7% agreed that cognitive enhancement is acceptable; 2.4% of the total sample said they had taken prescription drugs to enhance their concentration or alertness in the absence of a diagnosed disorder, and a further 8% said they knew someone who had done so. These participants were twice as likely to think cognitive enhancement was acceptable. Only 3.6% of participants agreed that people who play professional sport should be allowed to use performance-enhancing drugs if they wanted to. Participants who found cognitive enhancement acceptable were 9.5 times more likely to agree with legalized doping. Conclusions: Policies that facilitated the use of prescription drugs by healthy people for cognitive enhancement or permitted performance-enhancing drugs in sport would be at odds with the attitudes of the vast majority of our participants. Furthermore, our findings do not support media claims that the use of prescription drugs for cognitive enhancement is widespread in all sectors of society.