This study explored the influence of speech rate (normal vs. fast), sentence length (short vs. long), and second language (L2) oral proficiency on listening comprehension in L2 Spanish. Thirty-one native English-speaking learners enrolled in upper-level Spanish courses were aurally exposed to 8 sentences of each type of speed--length matrix, for a total of 32 sentences in Spanish. Listeners' comprehension was measured through native language recall following each sentence. Generalized estimating equations revealed that sentence length and oral proficiency were both significant predictors of listening comprehension in L2 Spanish, as were speed x oral proficiency and length x oral proficiency interactions. While lengthier utterances decreased comprehension, the extent of their influence was impacted by L2 oral proficiency, as measured by a standardized test. High oral proficiency helped to combat the negative effect of lengthier utterances. Moreover, accelerated speech degraded listening comprehension for higher proficiency participants only--not for their lower proficiency counterparts due to the latter's low comprehension scores at both normal and fast rates of sentence delivery. The results are discussed in light of previous empirical studies on listening ability. The current study contributes to the recent exploration of the variables involved in the complex process of L2 listening comprehension, discusses implications for pedagogy and the creation of listening materials, and suggests avenues for future research.