The Tax Assessor-Collector, elected by registered voters of Montgomery County for a four-year term, holds the Constitutional Office charged with duties and responsibilities mandated by State Statutes to assess and collect ad valorem tax accounts as identified and valued by the Montgomery Central Appraisal District. The office collects property taxes for 80 taxing jurisdictions (schools, cities and special districts). The Montgomery County Tax Office also collects beer, wine, and liquor licensing fees, and occupational taxes relating to vending machine permits. Acting as an Agent for the Texas Department of Motor Vehicles (TxDMV), all vehicle and trailer registration and titles are processed in this office for residents of the county.

In addition, on behalf of the County and other governing bodies, the Tax Assessor-Collector processes all Tax Abatement Agreements and bi-annual reports to ensure that each party to the Agreement is in compliance with their Agreement and County policy.The main Tax Office in Conroe, along with the five branch offices in Magnolia, Montgomery, New Caney, The Woodlands, and Willis, are open Monday through Friday (except holidays) from 8:00 A.M. to 4:30 P.M.. There are also 26  Neighborhood Registration Locations throughout Montgomery County; these locations are normally open 7 days a week during the regular business hours of the merchants' courtesy booths.