A water bottle cage assembly having a mounting bracket for releasable attachment to a bicycle frame tube. The cage assembly is shaped to receive a flexible, resilient water bottle in a releasable interference fit and includes an inboard segment having a pair of substantially parallel, longitudinally-extending struts, each strut having an offset portion extending outwardly from the cage, which is received by the mounting bracket in a pair of unitary recesses. The bracket preferably includes a pair of flexible straps positioned opposite to each other and joined by nut and bolt combinations at their ends to clamp the frame tube therebetween. At least one strap member includes the recesses which receive the offset portions such that they are clamped against the frame tube. The offset portions space the cage from the frame tube and provide clearance between the water bottle and the mounting bracket.