Traditional pronunciation instruction and instruction in second language (L2) phonetics have been shown to improve learners' L2 accent in some, though certainly not all, cases. Learners in intermediate and advanced Spanish FL courses have shown modest improvement in the pronunciation of some L2 phones after receiving such instruction. However, relatively less is known about how Spanish learners "perceive" L2 phones or how their perception changes over time and in response to instruction. Yet instruction might improve learners' ability to perceive, not just produce, L2 phones in more target-like ways. Furthermore, target-like perception may be a necessary precursor to target-like L2 production, as is suggested by several models of L2 phonological acquisition, most notably Flege's Speech Learning Model. This study reports on the advantages that first-, second-, and third-year learners of Spanish as an FL (n = 95) gained from explicit instruction in Spanish phonetics. Their performance was compared with a control group that received similar input, practice, and feedback but did not receive explicit instruction in Spanish phonetics. The target phones included a variety of consonants that have proven problematic for L1 English speakers: stop consonants, approximants, and rhotics. Learners' perception and production of the target phones were measured in a pretest, posttest, delayed posttest design using multiple elicitation tasks: an AX discrimination task, an identification task, and a word list reading production task. Whereas learners in both groups improved their pronunciation equally, the explicit phonetics instruction conferred an advantage for learner's discrimination and identification of the target phones. The results suggested that the benefit of explicit phonetics instruction was related to perceptive abilities more than productive abilities for several target phones. Instruction was equally beneficial for learners at different matriculation levels, indicating that phonetics lessons could be inserted at multiple stages along the Spanish FL curricular sequence. Finally, given that the experimental and control groups did not differ greatly for many of the tasks and phones, it was argued that a range of instructional methodologies should be explored as viable alternatives to explicit phonetics instruction for improving Spanish learners' accent. [The dissertation citations contained here are published with the permission of ProQuest LLC. Further reproduction is prohibited without permission. Copies of dissertations may be obtained by Telephone (800) 1-800-521-0600. Web page: http://www.proquest.com/en-US/products/dissertations/individuals.shtml.]