Katyayani Puja is a Hindu ritual that is performed to worship Goddess Katyayani, who is one of the nine forms of Goddess Durga. Goddess Katyayani is also known as Mahishasurmardini, as she killed the demon Mahishasura who had terrorized the gods and humans.

Katyayani Puja is usually done on the sixth day (Shashthi) of Navratri, which is a nine-day festival that celebrates the different aspects of Goddess Durga. It falls in the months of September-October (Ashwin) or March-April (Chaitra). On this day, devotees offer prayers, flowers, fruits, sweets etc., to Goddess Katyayani and seek her blessings for a happy and prosperous life.

Katyayani Puja is also considered very auspicious for unmarried girls and women who wish to get married soon. It is believed that Goddess Katyayani fulfills their desires and removes any obstacles or doshas that may be causing delays or problems in their marriage. Many girls and women observe a fast on this day and chant mantras dedicated to Goddess Katyayani.

The puja vidhi or procedure for Katyayani Puja involves waking up early in the morning and taking a bath. Then, a wooden plank is covered with a red cloth and an idol or picture of Goddess Katyayani is placed on it. The idol or picture is decorated with flowers, vermilion, turmeric etc., and a lamp is lit in front of it. The devotees then invoke Goddess Katyayani by reciting her names and offering her water, milk, honey etc., as part of the shodashopachara puja (sixteen steps of worship). They also recite various mantras such as Om Hreem Shreem Kleem Kaatyaayanee Swaahaa or Om Kaatyaayanee Namah while offering flowers or akshata (rice grains) to her. They then perform an aarti (a ritual of waving lamps) and distribute prasad (sacred food) among themselves.

The colour associated with Katyayani Puja is grey, which symbolizes strength, dignity and protection. The devotees wear grey clothes on this day to please Goddess Katyayani.