A fixing assembly is adapted to fix a main body of a roller shade to an environment, and is adapted to be installed at an end of a roller tube of the main body. The fixing assembly includes a fixing member, which corresponds to the roller tube when installed, and a fixing support corresponding to the fixing member. The fixing member includes a connecting portion and a snap-fitting portion connected to the connecting portion with an end thereof exposed out. The connecting portion can be connected to the end of the roller tube, whereby to fix the fixing member to the roller tube. The fixing support includes a fixing portion and a snap-fitted portion provided on a surface of the fixing portion facing the fixing member. The snap-fitting portion is detachably connected to the fixing support, and can be optionally engaged with the snap-fitted portion at different positions.