The current study examines how second language (L2) users differentially assess the comprehensibility (i.e., ease of understanding) of foreign-accented speech according to a range of background variables, including first language (L1) profiles, L2 proficiency, age, experience, familiarity, and metacognition. A total of 110 L2 listeners first evaluated the global comprehensibility of 50 spontaneous speech samples produced by low-, mid-, and high-proficiency Japanese speakers of English. The listeners were categorized into two subgroups according to a cluster analysis of their rating scores: lenient and strict. Results showed that while the lenient listeners appeared to rely equally on many linguistic areas of speech during their judgments, the strict listeners were strongly attuned to phonological accuracy. Analysis of the background questionnaire data revealed that more lenient listeners likely had higher levels of awareness of the importance of comprehensibility for communication (metacognition); regularly used L2 English in professional settings (experience); and had L1s more linguistically close to the target speech samples, Japanese-accented English (L1-L2 distance).