Students acquiring American Sign Language (ASL) as a second language (L2) struggle with fingerspelling comprehension more than skilled signers. These L2 learners might be attempting to perceive and comprehend fingerspelling in a way that is different from native signers, which could negatively impact their ability to comprehend fingerspelling. This could be related to improper weighting of cues that skilled signers use to identify fingerspelled utterances. Improper cue-weighting in spoken language learners has been ameliorated through explicit phonetic instruction, but this method of teaching has yet to be applied to learners of a language in a new modality (M2 learners). The present study assesses this prospect. Eighteen university students in their third-semester of ASL were divided into two groups; one received explicit phonetic training, and the other received implicit training on fingerspelling. Data from a fingerspelling comprehension test, with two experimental conditions and a control, were submitted to a mixed effects logistic regression. This revealed a significant improvement from the pre-test to post-test by students who received the explicit training. Results indicate that even short exposure to explicit phonetic instruction significantly improves participants' ability to understand fingerspelling, suggesting that ASL curricula should include this type of instruction to improve students' fingerspelling comprehension abilities.