Advertisers have turned attention to the popular photograph-based social network Instagram. One technique for reaching consumers has been advertisements resembling posts one’s friends might make. These native advertisements use Instagram’s conventions and may be unrecognized as sponsored messages at first glance, when browsing one’s Instagram. A within-subjects experiment (N = 482) tested these native ads against both user-generated posts and traditional advertisements. These message types were presented in a repeated-measures design, rotated across three well-known brands, and interspersed with distractor posts. Results indicated that the three message types produced similar effects on ad attitude, brand attitude, and behavioral intention. However, user-generated social posts produced more credibility and social comparison than native ads, and native ads produced more credibility and social comparison than advertisements. This yielded indirect effects on dependent variables of interest, despite the lack of total effects. Sponsorship recognition was relatively high for native ads but did not mediate effects.