My employer pays overtime on a decreasing scale, (the more hours the lower the rate) and make us work 10 hours a day, is this legal in Texas?

Probalby not. But just so we're clear on a couple of things: 1) Overtime is governed by federal law under the Fair Labor Standards Act (FLSA) 2) For most employers, the FLSA says that employees must be paid at a rate of 1.5 times their regular houly rate for all hours worked in excess of 40 each week 3) This means that overtime does not kick in until an employee has worked 40 hours in a week.  So if an employer worked an employee 10 hours per day for 4 days and then let her have the rest of the week off, no overtime would be due. 4) There are some execeptions for professional and managment salaried employee, but they don't sound like they apply to your question.  I have never heard of an employer paying a declining overtime rate based on the number of overtime hours worked.  I have no reason to think it is legal.  If this is just happening to you, I suggest you report the situation to the US Department of Labor, Wage & Hour Division.  There is an office in each major city in Texas (DFW is in Arlington).  https://www.dol.gov/whd/america2.htm#Texas.  They will investigate and try to recover the unpaid wages. If this has happened to many employees in your company, you may also consider gathering 3-5 of them and seeking out an attorney with experince in bringing a collective action (kind of a class action) under the FLSA on behalf of all employees that were treated in this manner.  The penalty to the employer is 2x the unpaid wages (for up to 3 years) plus attorneys fees.