Lately, she said, she and other students had felt uncomfortable about reassuring those prospective students that they would feel welcome at Harvard.

“We need more than just letting us in,” said Ms. Veira-Ramirez, who came to the United States from Colombia when she was 3 years old. Ms. Veira-Ramirez, who is undocumented, has protection from deportation under Deferred Action for Childhood Arrivals, an Obama-era program that protected young undocumented immigrants.

“We need resources once we get to campus,” she said, “and part of those resources is an ethnic studies program.”

The students have not been alone in voicing concern over the decision to deny tenure to Dr. García Peña. Scholars from around the country have written to Harvard’s president expressing dismay with the decision, and Harvard faculty have demanded a review of the tenure process, with an eye to whether it is undermining the university’s effort to diversify its faculty.

Dr. García Peña declined to comment, as did a spokeswoman for Harvard.

Lawrence S. Bacow, Harvard’s president, has declined to discuss the reasons for denying Dr. García Peña tenure, citing the confidentiality of the process. The dean of the Faculty of Arts and Sciences, Claudine Gay, has said that she wants to increase offerings in ethnic studies but believes that hiring more faculty must come first, before creating a new major. Last June, she announced that Harvard would hire three to four new faculty working in ethnic studies; the search is still continuing. Dr. Gay also said in response to the faculty concerns that she would conduct a review of the tenure process.

Just 81 of Harvard’s 2,490 faculty members identify as Hispanic, according to Harvard’s Fact Book; the university would not say how many of those are tenured. According to a 2019 report on faculty diversity, 8 percent of the roughly 1,000 tenured faculty are underrepresented minorities, which includes people who are black, Latino and Native American. Of the tenure-track faculty, 12 percent are underrepresented minorities.

The controversy echoes recent conflicts at other schools. At Yale last March, 13 professors withdrew from the university’s Ethnicity, Race and Migration program, citing a lack of support; the professors later rejoined the program after the university agreed to increase its resources. At Dartmouth, an English professor who specialized in Asian-American studies was denied tenure in 2016, setting off an uproar among students and faculty about the college’s failure to attract and retain faculty of color and the treatment of faculty who specialized in the studies of race, gender and sexuality.