The paper reports on a study of a harmonic oscillator (ho) in the twisted Moyal space, in a well defined matrix basis, generated by the vector fields X a = e µ a (x)∂ µ = (δ µ a + ω µ ab x b )∂ µ , which induce a dynamical star product. The usual multiplication law can be hence reproduced in the ω µ ab null limit. The star actions of creation and annihilation functions are explicitly computed. The ho states are infinitely degenerate with energies depending on the coordinate functions.