Language placement test serve with multiple purposes to measure the language abilities and performance of language learners to place them in the most appropriate language course with curriculum that best meets the language needs. There is the need to assess appropriately the Spanish heritage language learners' (SHLLs) abilities at the high-school level. Therefore, this mixed-method study investigated how Thompson's (2015) modified Yes or No 10-question Survey of Language Usage (Survey) and the three part Spanish for Heritage Language Learners Placement Program Exam (Placement Test) could be used effectively with three Spanish class levels of HLLs at the high-school level to differentiate HLLs' use of Spanish inside and outside of the home and in their academic use of Spanish. The three placement test parts were (a) Language Awareness (LA); (b) Bilingual Skills (BS) and (c) Writing Skills (WS). The independent variables were the three classifications of the survey and the three SHLL classes, and the dependent variables were the scores for LA, BS and WS. A total of one hundred forty-four 9th- through 12th- grade Spanish-speaking heritage language learners enrolled in Pre-International Baccalaureate (Pre-IB) Spanish for Heritage Learners Level 1 (Pre-IB SHLL I), Spanish for Heritage Learners Level I (SHLL I), and Spanish for Heritage Language Learners Level II (SHLL II) classes participated in the study taking the Thompsons' modified Survey and Placement Test. Four Spanish teachers with diverse teaching experience participated in the pre- and postfocus group interviews evaluating the benefits and challenges of the existing placement system and the new implementation of Thompsons' modified instruments. The findings of the Survey show that only 33% of SHLLs were correctly placed and approximately 66% were misplaced. Cohen's kappa (k) results also showed that there was no statistically significant agreement between the survey results and the existing class placement, k = 0.04. One of the major findings of the placement test results indicated that there were only mean differences in Bilingual Skills (BS) based on the three SHLLs classes. The practical importance (Eta squared) for BS is 0.04, which is a small size according to Cohen's criteria. Due to the major possibility that 34 participating students could have used Google Translate for Part II: Bilingual Skills, additional analyses were performed. The independent-sample t-test results show that there was a statistically significant mean difference between the SHLLs group who did not use Google Translate (n = 110) and the group who possibly did use it (n = 34). The findings from the pre- and postfocus teachers' interviews revealed a total of 19 themes and three subthemes. They have mixed equivalence on the benefits and challenges of the existing and the new implementation of the placement systems; however, one major benefit of the new placement systems was the implementation of rating rubrics for more appropriate assessment of the SHLLs skills and an equitable placement system. Due to the unprecedented COVID-19, however, the findings also indicated that a major factor that possibly influenced the results of the study was being in distance learning. [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://bibliotheek.ehb.be:2222/en-US/products/dissertations/individuals.shtml.]