No percentage cap, but an unusually worded standard
Texas has no statutory cap on contingency fee percentages in ordinary personal injury cases. The exact numbers are set by the signed fee agreement, not by any statute. The governing standard, Texas Disciplinary Rule 1.04(a), specifically prohibits an "unconscionable" fee — a notably stronger-sounding term than the plain "unreasonable fee" language many other states use, though a separate list of reasonableness factors still informs how that standard gets applied in practice.
What the written agreement must include
Rule 1.04(d) requires that a contingency fee agreement be in writing and specifically state how the fee is calculated, listing each percentage that applies depending on how the case resolves — at settlement, at trial, or on appeal — along with how expenses will be handled. A typical Texas agreement sets different percentages for each stage, since a case that goes to trial or appeal generally involves substantially more attorney work than one that settles early.
What a typical fee looks like
One-third of the recovery is a commonly used figure in Texas personal injury practice, though it isn't fixed by statute and can vary based on case complexity and which stage the case resolves at.