A tube fitting includes a multi-way tube member and a coupler. The multi-way tube member includes three interconnected tube-connecting segments, one of which has two locking portions disposed at a distal end thereof. The coupler includes a cap section covering one of the tube-connecting segments having the locking portions, two resilient retaining portions snapped respectively to the locking portions, a guide tube section extending from the cap section into the one of the tube-connecting segments, and a connecting tube section extending from the cap section in a direction away from the guide tube section for connection with an additional coupler. A curable filler can be filled among the multi-way tube member, the coupler, and a tube for fixing the tube within the multi-way tube member.
