This study attempted to answer the following research questions related to the various vocabulary discovery strategies which are used by Saudi undergraduate learners to find unknown word meanings, the most and the least vocabulary discovery strategies the learners used to discover unknown word meanings, the relationship between the type of Vocabulary Learning Strategies used and the scores the learners accomplished on the vocabulary test, and effectiveness of the learner control and the teacher control strategy in enhancing learners' ability to discover meanings of unknown words. Answering these questions of the study are expected to help language instructors determine the most feasible vocabulary learning strategies to help their students improve their vocabulary and so their language competences. Through purposive sampling, a group of 50 male students participated in this descriptive and analytic type of study. A questionnaire and a vocabulary test were used to collect data. The findings of the study revealed that in understanding a reading text, EFL Saudi students tend to figure out the meanings of unknown words, mainly by guessing word-meanings through different sub-strategies. The least used was the social interaction strategy. It was also found that students' scores on the vocabulary test significantly correlated (positively and negatively) with the type of strategy they used. This study concluded that it is vital for teachers and textbook writers to design more activities to train students on the use of effective vocabulary learning strategies, mainly guessing through socially linked contextual clues.