A weather strip having a trim portion capable of decreasing an insertion load of a flange and increasing a removal load thereof where the thickness of the flange varies, thereby preventing its turn against a flange. The weather strip has a trim portion and a seal portion. The trim portion has a generally U-shaped cross-section. An inner holding lip includes a base part, a main lip formed along an end of the base part, and a sub-lip formed from a side surface of the end of the base part so as to project obliquely with respect to the main lip in a direction of the opening of the trim portion. The sub-lip is made shorter than the main lip, and an end of the sub-lip is located on the opening side of an interior surface of a joint between the base part and the inner side wall.