Agnes Ida Pettersen (born 1981) is a Norwegian composer. She mainly writes for acoustic instruments, but also works in electronic music, installations and music for the stage.

She studied composition at the Norwegian Academy of Music with Bjørn Kruse and Henrik Hellstenius as her primary teachers. Since 2011, she has worked as a freelance composer based in Oslo. Her work In b was performed at the Nordic Music Days festival in 2015. Her piece I det stille // Epilog has been recorded by Telemark kammerorkester and performed by Det norske kammerorkester. She has also worked with Det Norske Blåseebsemble, Felicia Kaijser, Ingvild Maria Mehus and NOSO Sinfonietta.