January 15th -- Due date for 4th estimated tax payment for prior tax year

January 31st -- Due date for Forms W-2's
                        -- Due date for Forms 941 and Texas Workforce Commission filings for the 4th quarter of the prior year
                        -- Due date for Forms 940
                        -- Due date for Forms 1099

March 15th -- Due date for corporate tax returns (may be extended to September 15th with estimated payment)

April 15th -- Due date for personal & partnership tax returns (may be extended to October15th with estimated payment)
                   -- Due date for 1st estimated tax payment for current tax year

April 30th -- Due date for Form 941 and Texas Workforce Commission filings for the 1st quarter of the current year

May 15th -- Due date for Texas franchise tax returns

June15th -- Due date for 2nd estimated tax payment for current tax year

July 31st -- Due date for Form 941 and Texas Workforce Commission filings for the 2nd quarter of the current year

September 15th -- Due date for 3rd estimated tax payment for current tax year
                               -- Due date for extended corporate tax returns         

October 15th -- Due date for extended personal and partnership tax returns

October 31st -- Due date for Form 941 and Texas Workforce Commission filings for the 3rdt quarter of the current year

November 15th -- Due date for extended Texas franchise tax returns

Notice: If any due dates fall on a Holiday or weekend, the deadline is extended to the following business day.