Gprof is a performance analysis tool used for profiling applications written in C and C++. It helps developers understand where their programs spend most of their execution time, allowing them to identify bottlenecks and optimize performance. By generating a call graph, Gprof shows the relationship between functions and how much time is spent in each. To use Gprof, developers compile their code with specific flags to enable profiling. After running the program, Gprof produces a report that details function call counts and execution times. This information is crucial for improving the efficiency of software applications.