Answer: We need to first define the two terms in question before delving into what God's word teaches. Horoscopes offer advice to people regarding what may happen to them in the future. Astrology is the study of the heavens (sun, moon, planets, etc.) and their motions under the assumption that they influence events and human activities on earth.
Unlike astronomy, which is the scientific study of the universe, astrology is based on a person's interpretation and the meaning they read into what they observe. Begun in ancient Mesopotamia, it is man's feeble attempt, apart from God, to try to predict future events through distant stars and other heavenly bodies.
Although the Encyclopedia Britannica states that astrology first occurred in the third millennium B.C. other reference works disagree. The encyclopedia quotes a warning, based on the stars, given to King Ashurbanipal of Assyria in the 7th century B.C. that states, "The planet Venus is approaching the constellation Virgo. The appearance of the planet Mercury is near. Great wrath will come."
Horoscopes are related to astrology in that they attempt to predict a person's future based on the time they were born and the movement of the heavens. The word itself is derived from the Greek meaning "one who observes the hour." Our current form of horoscopes is really a Greek addition to earlier ideas, such as seeing the sun's path in the sky move through the twelve houses of the zodiac. As an interesting side note, God's word alludes to the zodiac in Job 38:32.
The idea that heavenly bodies control our destiny, rather than a God who is the Creator of all things, is an ancient delusion. Augustine, the famous Catholic theologian and philosopher who lived when Rome was in decline, and Cicero, the pagan orator of the Roman Republic, made a point of attacking this belief.
Although Scripture does not use the word astrology, it does refer to its practice. For example, the book of Daniel references astrologers serving at the court of King Nebuchadnezzar (Daniel 2:27, 4:7). As one would expect, the belief that anything other than the true God steers the destiny of man is rejected in Scripture.
What few people realize is that the Bible considers astrology, or consulting the heavens for guidance regarding future actions and events (like horoscopes attempt to do as well), as a form of sorcery (Leviticus 19:26 - 28, 31, 20:6).
God directly warned ancient Babylon about trusting in astrology when he said, "You are exhausted by the multitude of your counsels; now let the astrologers, the stargazers, the monthly prognosticators (e.g. those who create horoscopes), stand up, and save you from these things that shall come upon you" (Isaiah 47:13, HBFV). Ancient Israel was also warned directly about such practices.
There shall not be found among you anyone who makes his son or his daughter to pass through the fire (human sacrifices!), or that uses divination, or an observer of times (like astrology), or a fortuneteller, or a witch, or a charmer, or a consulter with familiar spirits, or a wizard, or one who seeks oracles from the dead.
For all that do these things are an abomination to the Lord (Deuteronomy 18:10 - 12, HBFV).
Astrology and horoscopes do nothing more than pretend to foretell future events based on the absurd idea that celestial bodies, billions of miles away, can have some sort of magical impact on earth. They both, according to the Bible, should be completely avoided as they are a waste of time!