The suit filed in Austin, Texas, Friday by Betty Domingo claims one of the women -- Brenda Mitchell of Lubbock -- invited Domingo to join a "group of ladies" pooling their lottery money and initially told Domingo she would share in the April 29 jackpot.
But Mitchell later reneged, saying she didn't have enough money to buy tickets for Domingo after buying something to eat the day the winning ticket was purchased, the Austin (Texas) American-Statesman reported.
Domingo's suit claims that -- when she and Mitchell paid for each other's tickets -- they agreed to repay the other and share any lottery winnings.
The suit names the six women, who elected to take a $20.9 million lump-sum payment, and the Texas Lottery Commission.
A Travis County, Texas, judge issued a restraining order barring distribution of the money pending a hearing next week.