The highest of the three LDS kingdoms of glory in heaven where a person will live eternally with Heavenly Father and Jesus. Qualifications for entering this kingdom depends “on the depth of your conversion, expressed by your obedience to the Lord's commandments. ... Such a goal is not achieved in one attempt, it is the result of a lifetime of righteousness and constancy of purpose" (True to the Faith, p. 92).
There are three levels within the celestial kingdom: the top level equals exaltation (godhood), the purpose of the second level has not been revealed, and the third level is for faithful Mormons who were not married in the temple. These individuals become ministering servants.
Biblical Christianity teaches that all who go to heaven will live with God. There is only one kingdom of glory, not three. People will be able to live with God, not because of anything they have done, but all because of what Jesus has done for them.