This study investigates the influence of social media influencers and celebrity endorsements on attitudes and intentions to purchase high and medium-involvement products on Instagram. A multimethod research design was used, with a national sample of 799 Instagram users. Results show that celebrity endorsements are more impactful than social media influencers for High and medium-involvement products. However, social media influencers influence more males, but attitudes remain consistent across genders. Celebrity endorsements and influencers have the highest impact on Millennials. The study reveals that celebrities are more influential than celebrity endorsements for medium-involvement products. There are significant gender and age differences but no ethnic differences. Males are more influenced by celebrities and influencers on Instagram, but their attitude toward influencers remains consistent. Celebrity endorsement and influencers have the highest impact on Millennials, followed by Gen X, baby boomers, and Gen Z, with no significant difference between Gen Z and baby boomers.