Coach Tim Miles announced Tuesday that both would join the program next season.
The 6-foot-1, 180-pound Allen was the No. 100 recruit by ESPN. Allen, originally from Raleigh, North Carolina, averaged 18 points per game and shot 48 percent on 3-pointers last season.
The 6-8, 230-pound Okeke holds Winthrop shot-blocking records and averaged 3.2 points and 3.9 rebounds per game last season.