Hypothesis is a single statement regarding relationship between variables that can be tested by observation. Hypotheses are usually formulated to support or deny theories. Usually,  several hypotheses on a fact, if scientifically proven, become a theory.

A theory, on the other hand, is a systematic set of generalization that explains some phenomenal linking variables in order to come up with principles that are internally consistent. It should be noted that a theory is only accepted after successful researches on  a certain formulation about a fact are done while a hypothesis is just a mere formulation of a fact.