Despite the importance of understanding plant growth, the mechanisms underlying how plant and fruit growth declines, during drought remains poorly understood. Specifically, it remains unresolved whether carbon or water factors are responsible for limiting growth as drought progresses. We examine questions regarding the relative importance of water and carbon to fruit growth depending on the water deficit level and the fruit growth stage, by measuring in olive fruit diameter, leaf photosynthesis, a proxy of cell turgor and flow cytometry to determine the fruit cell division stage. We found that photosynthesis and turgor were related to fruit growth; specifically, the relative importance of photosynthesis was higher during periods of more intense cell division, while turgor had higher importance in periods where cell division comes close to ceasing, and fruit growth is dependent mainly on cell expansion. This pattern was found regardless of the water deficit level, although, turgor and growth ceased at more similar values of leaf water potential than photosynthesis. We conclude that carbon and water processes are able to explain fruit growth, with importance placed on the combination of cell division and expansion. However, the major limitation to growth is turgor, which adds evidence to the sink limitation hypothesis.