The G minor key signature consists of two flats, specifically B flat and E flat, and it signifies that music composed in this key has a minor tonality based around the G note. This key is often characterized by its emotional depth and can evoke feelings of melancholy or introspection, which is common in many musical styles. Understanding the G minor key signature is essential for recognizing the relationship between major and minor keys, as well as how to identify relative major keys and modulation techniques.