The Knesset Eliyahoo Synagogue (Hebrew: בית הכנסת אליהו, lit. 'Gathering of Elijah'), also Knesset Eliyahu and the Blue Synagogue, is an Orthodox Jewish congregation and synagogue, located at 55, Dr. V.B. Gandhi Marg, in the Kala Ghoda neighborhood, Fort, in downtown Mumbai, in the state of Maharashtra, India. Completed in 1884, it is the second oldest Sephardic synagogue in Mumbai. The Taj Mahal Palace Hotel, and Oberoi Trident are nearby.
The synagogue was established by Jacob Elias Sassoon and the building is maintained by the Jacob Sassoon Trust. The building's significance is attributed to its Jewish traditions as well as Indian and English colonial influences. It was designed by the British architectural firm Gostling & Morris of Bombay. The basement part of the edifice is built in stone masonry and the superstructure is built in brick masonry. The exterior facade of the synagogue was painted turquoise, was returned to its original colour of white, with bright indigo boarders during a restoration process in 2018–2019. The sanctuary within the interior of the building is in western direction, towards Jerusalem.
