follows middle-schooler Greg Heffley as he navigates a year of social challenges, friendships, and family life, all while chronicling his experiences in a diary filled with illustrations. The synopsis centers on Greg's attempts to become more popular, which often backfires and creates humorous situations with his best friend, Rowley Jefferson. The book humorously explores the awkwardness of growing up and the complex social structure of middle school.

The Diary of a Wimpy Kid movie synopsis differs from the book primarily through plot changes, the addition of new characters, and altered characterizations for a more cohesive narrative structure. Key differences include the movie version creating a more central storyline around Greg and Rodrick's relationship and the expansion of minor characters like Chirag and Patty to have more significant roles. For example, the film adds the character of Angie to provide a different perspective on popularity, while certain book events are rearranged or omitted to better fit the movie format.