Big Brother 4 is the fourth season of the Croatian reality television series Big Brother that began on 7 September 2007 and ended on 21 December 2007.

The maximum prize was 1.5 million HRK (200 000 EUR).

Every successful weekly task increased the final prize by the same amount.

Producers introduced penalties as a response to criticism of the second season, when they were perceived to be too tolerant of contestants' misbehavior.

In the fourth season 14 housemates entered the house.