Yes, getting drunk is a sin. The Bible identifies drunkenness as behavior that is against God's wishes and plans for us (1 Corinthians 6:10). People who follow Jesus should not get drunk, practice immorality, or worldly thinking (Galatians 2:20; Romans 6:1–6).
The Bible tells us that getting drunk violates God's command (Proverbs 20:1; 23:20, 29–32; Isaiah 5:22; Ephesians 5:18). However, we are not called to follow rules, but to follow Jesus Christ (Luke 11:42; Matthew 23:23). Our love for our Savior should lead us to be more like Him (1 Peter 1:15).
In Ephesians 5, we can read several comparisons of serving God and not serving God. In at least one passage, drunkenness is addressed: "And do not get drunk with wine, for that is debauchery, but be filled with the Spirit" (verse 18). When we see the dichotomy between drinking and being filled with the Spirit, we have a choice to make.
When we drink alcohol, we lose an increasing amount of self-control—and self-control is one of the fruits of the Spirit (Galatians 5:22–23). Christians should not divide themselves between being controlled by the Spirit and by any amount of mind-altering substances.
Though getting drunk is clearly prohibited in Scripture, many Christians also wonder about drinking alcohol in moderation. In many passages, those who are set apart for service to God were instructed to totally abstain from alcohol (Judges 13:4; Leviticus 10:9; Luke 1:15). In Proverbs 20:1 and 31:4, the writer warns about the effects of drinking. In other places, we see Christ-followers drinking alcohol. Jesus turned water into wine at the wedding in Cana (John 2:1–12). Paul told Timothy, "No longer drink only water, but use a little wine for the sake of your stomach and your frequent ailments" (1 Timothy 5:23). Many Christians, following God's call to be holy, have determined to abstain from any and all amounts of alcohol. Others choose to drink in moderation. Either way, it is clear that being controlled by alcohol or becoming drunk are not what God has in mind for His people.
When we give ourselves over to alcohol, we are allowing something else to have mastery over us. Jesus said we cannot serve two masters (Matthew 6:24) and must focus and serve just one. Christians determine to serve Jesus, and Him only.