Head Start Expansion and Improvement Act of 2026 This bill reauthorizes through FY2032 and otherwise revises Head Start programs. Specifically, the bill expands eligibility for Head Start programs to include families with incomes below 138% of the federal poverty level. The bill also adds a definition for public assistance under the Head Start Act to include Temporary Assistance for Needy Families (TANF); Supplemental Security Income (SSI); the Supplemental Nutrition Assistance Program (SNAP); the Special Supplemental Nutrition Program for Women, Infants, and Children (WIC); or the Children’s Health Insurance Program (CHIP). The bill directs the Department of Health and Human Services (HHS) to establish a program to make grants to Head Start agencies (including Early Head Start agencies) to construct or improve facilities. HHS must also establish and carry out a program to make grants to Head Start agencies for increasing the compensation paid to employees. The bill also provides student loan forgiveness for certain Head Start and Early Head Start child care workers. In particular, the Department of Education must cancel the outstanding balance of principal, interest, and fees due on Federal Direct Loans for a borrower who (1) has been employed full-time by a Head Start or Early Head Start program for three years, and (2) has provided care or instruction to children enrolled in such a program.