During a meeting Thursday night, the district revealed 197,000 students are enrolled.
That's down about 12,000 students from previous district estimates.
Interim Superintendent Dr. Grenita Lathan did not give a specific reason for the drop, but districts across Texas have seen a decline with forced virtual school for many.
According to HISD, 40% of students are learning in-person and 60% learning virtually this semester.
ABC13 compared the first grading period from this year to last year, and the number of students who got at least one "F."
RELATED: HISD says 42% of its students failed one or more classes during first grading period
For example, in Aldine ISD and Pearland ISD, the number of failing students more than doubled.
Aldine ISD reported 11,418 students who had at least one "F" in first grading period in 2019 and 25,390 in 2020. Pearland ISD reported 1,332 in 2019 and 3,610 in 2020.
Ahead of Thursday's meeting, HISD swore-in a new trustee.
In a unanimous decision, Houston Independent School District trustees voted to appoint attorney Myrna Lynn Guidry to the empty District IX board seat.
The seat was vacated last month by Wanda Adams, who resigned following her election as a justice of the peace.
Guidry has operated a private practice focusing on family and probate law for the past two decades.
She will fulfill Adams' term which ends on Dec. 31, 2021.
SEE ALSO: Houston-area school districts search for ways to help students who failed 1 or more classes