Fill-in can refer to:

• A puzzle, see Fill-In (puzzle)
• In numerical analysis, the entries of a matrix which change from zero to a non-zero value in the execution of an algorithm; see Sparse matrix#Reducing fill-in
• An issue of a comic book produced by a different creative team than the one regularly assigned to the series, published either to avoid missing a deadline or to give one or more of the series's regular creators a break

• Fill (disambiguation)
• Filling-in

This disambiguation page lists articles associated with the title Fill-in.
If an internal link led you here, you may wish to change the link to point directly to the intended article.