I didn’t really like this one. There are some moments in 'Horton Hears a Who!' that weren't terrible, but mostly I thought this movie from 2008 was pretty dull. Jim Carrey, who I usually enjoy watching, doesn't work well in the part, and his storyline became quite tedious for me. The scenes featuring Steve Carell’s Mayor—who is also a bit disappointing, though not as much—were the most engaging, but there were so many segments focused on Horton that I couldn't even get into that portion of the story. The rest of the actors, despite including some familiar faces, aren't particularly good either. I’ve clearly had trouble with movies based on Dr. Seuss stories, and only 'The Cat in the Hat' is one that I genuinely like—I realize I’m an outlier on this opinion, but don't argue with me 😂. This film was disappointing, to be honest.

Source on TMDB