This is from the Dallas Business Journal. Schools had to return a survey in order to be ranked. Tuition amount is the maximum tuition at the school (tuition will vary by grade level).
Rank) Tuition - School (City) - Enrollment
1) $27,457 - St. Alcuin Montessori (North Dallas) - 490
2) $25,972 - Episcopal School of Dallas (North Dallas) - 1,167
3) $25,186 - St. Mark's School of Texas (North Dallas) - 852
4) $25,000 - The Winston School (North Dallas) - 210
5) $23,925 - The Hockaday School (North Dallas) - 1,085
6) $23,100 - Greenhill School (Addison) - 1,268
7) $23,000 - Oak Hill Academy (North Dallas) - 133
8) $22,790 - Shelton School (Far North Dallas) - 876
9) $21,500 - Parish Episcopal School (Far North Dallas) - 1,100
10) $20,800 - Ann and Nate Levine Academy (Far North Dallas) - 400
11) $19,155 - The Lamplighter School (North Dallas) - 440
12) $18,400 - Dallas International School (North Dallas) - 594
13) $18,375 - Trinity Valley School (Ft. Worth) - 960
14) $18,100 - The Dallas Academy (East Dallas) - 175
15) $18,060 - Ft. Worth Country Day (Ft. Worth) - 1,110
16) $17,700 - Hill School of Grapevine (Grapevine) - 83
17) $17,500 - Cistercian Preparatory School (Irving) - 355
17) $17,500 - Great Lakes Academy (Plano) - 80
17) $17,500 - Key School (Ft. Worth) - 100
20) $17,275 - The Oakridge School (Arlington) - 875
21) $16,770 - Cambridge School of Dallas (North Dallas) - 118
22) $16,725 - Lakehill Preparatory School (East Dallas) - 400
23) $16,650 - Hill School of Ft. Worth (Ft. Worth) - 173
24) $16,600 - Trinity Christian Academy (Addison) - 1,544
25) $16,530 - Prestonwood Christian Academy (Plano) - 1,455
26) $15,750 - Ursuline Academy of Dallas (North Dallas) - 800
27) $15,180 - St. John's Episcopal School (East Dallas) - 500
28) $15,000 - Fairhill (Far North Dallas) - 235
29) $14,975 - Ft. Worth Academy (Ft. Worth) - 240
30) $14,400 - The Canterbury Episcopal School (DeSoto) - 250