This paper investigates how corporate diversification affects a firm's growth options value. We adopt a real options approach from which diversification is seen as both a way to exploit current growth options (option exercise effect) and as a source of future options to expand (option creation effect). We focus on two dimensions of this strategy: degree of diversification and relatedness between segments. Using a panel sample of U.S. firms from 1998 to 2014, and accounting for the endogenous nature of the diversification decision, we find a U-form relationship between diversification degree and growth options value, suggesting that this strategy may primarily become a source of growth options after a certain point. Relatedness has an inverse U-relation with growth options value, suggesting that positive effects from synergies are limited to a certain level after which negative effects from duplicities prevail. Results also reveal that such an inverse U-linkage of relatedness is less pronounced in high diversifiers than in low ones. This study extends the applicability of the real options approach to strategy, and suggests the relevance of a multidimensional and contingent view in the diversification debate.