A micro-cantilever fabricated using a combination of ps-laser machining and Focused Ion Beam milling directly onto the end of a standard telecommunications optical fiber is demonstrated as a liquid pH sensor. Conventional pH meters typically require relatively large reaction volumes up to ~50 mL which is not always convenient. The micro scale nature of this sensor offers the potential for pH measurement on a smaller sample volume down to µL. The fiber end-tip cantilever is coated with a pH sensitive layer and the pH induced deflection is monitored interfermetically. A pH detectable range from pH 4.0 to pH 10.0 is demonstrated for cantilevers coated with 16-mercapto-hexadecanoic-1-acid MHA as the functional layer and pH 4.0 to pH 9.0 with Al2O3 as the functional layer.