In what order were the books in the New Testament written?

Paul's Letters were written first; 45-60s. Ephesians, likely pseudopauline, is late 1st century.

Mark is the first Gospel written, around 65. Luke (80s-90s) and Matthew (90s) are later. Acts is by the same author as Luke but written a bit later (90-100s).

Hebrews is anywhere from the 60 to 100.

James is probably 80s or 90s.

John's gospel is usually dated to 80s or 90s, but rival view says could around 70.

Titus, 1 Tim, and 2 Ti; "most scholars" (NOAB, 3rd ed) consider to have been written later than Paul, so in the late 1st century.

1 Peter, 1 John, and Jude are all late 1st century. 2nd Peter is by a different author and from early 2nd century. 2-3 John are also early 2nd century.

Revelation most likely written during the persecution of the 80s-90s.

All the dates, citations, and info are from the New Oxford Annotated Bible, ed Michal Coogan, 3rd edition.

My answer is from the point of view of critical scholars, in other words experts who have studied the New Testament texts to establish who really wrote them and when. Sometimes, these scholars come up with some surprising conclusions. I will list the New Testament books in approximate chronological order, but alter this when necessary for clarity.

It is generally accepted that Paul's 'undisputed' epistles (Romans, 1 Corinthians, 2 Corinthians, Philemon, Galatians, Philippians and 1 Thessalonians) were written by about 60 CE. 1 Thessalonians is believed to have been the first New Testament epistle that Paul wrote, and Romans probably the last. I can add to the confusion a little by adding that some scholars see references to additional epistles and believe that Second Corinthians, as it comes down to us today, is actually a combination of three separate epistles that Paul wrote. I shall return to the other epistles generally attributed to Paul and briefly describe why critical scholars date them after Paul's death.

Hebrews is usually dated quite early, although it is now generally accepted that Paul did not write this book. It was never attributed to him until late in the second century.

The Epistle of James is an enigma. Its primitive theology would place it quite early, but James 2:18-24 contains a sharp invective against anyone who maintains that it is faith alone that can put a person into a right standing before God. Bart D. Ehrman says in Forged, page 197, that the author of James was reacting to the theology in the Epistle to the Ephesians, therefore placing it somewhat later in time than that Epistle.

Which means this is now a good place to discuss the Epistle to the Ephesians and its sister epistle, Colossians. Alvar Ellegard says in Jesus One Hundred Years Before Christ, page 148, that many passages in Ephesians seem to be directly copied from the ‘presumably somewhat earlier’ Colossians. Burton L Mack says in Who Wrote the New Testament, page 183 that the letters to the Colossians and Ephesians are not authentic, and that there is not a suggestion of the real Paul in either of them. Scholars date Colossians to the 70s of the first century and Ephesians about ten years later.

There seems to be a fundamental disparity between the teachings of 1 Thessalonians and 2 Thessalonians, which is an important reason so many scholars think that 2 Thessalonians is not by Paul. This epistle is hard to date, but seems to belong in the last half of the first century.

To the surprise of many, the four New Testament gospels were all written anonymously, with none of them considered likely to have been written by an eyewitness to the events portrayed. Mark's Gospel is believed to have been written first, as it evidently was the primary source used by the authors of Matthew and Luke. John Dominic Crossan, in The Birth of Christianity, page 110-111, speaks of a massive consensus among scholars in favour of Markan priority. He says there is a smaller, but still substantial majority of scholars who believe that the hypothetical 'Q' document was the source of other material on which Matthew and Luke agree. Textual analysis allows the following date estimates

• Mark was written approximately 70 CE.
• Matthew was written during the 80s CE.
• Luke was written around the end of the century.
• John was written shortly after Luke. Some parts of this gospel appear to have been inspired by Luke.

The three Johannine epistles were written by the 'Presbyter' (or 'elder') shortly after the Gospel of John.

The 'Pastoral epistles', 1 Timothy, 2 Timothy and Titus provide pastoral advice appropriate for the church in the second century. They also use around two hundred words that came into use by Christian authors in the second century. On the basis of this information and other analysis, almost all New Testament scholars date these epistles to the second century.

Bart D. Ehrman says in Forged, page 68, that by the end of the first century Christians and Jews had started using the word Babylon as a code word for Rome, the city that also destroyed Jerusalem and its Temple in the year 70. This reference would have been meaningless to readers before the destruction of the Temple, so when 1 Peter 5:13 offers salutations from the church that is at Babylon, the author really was writing from Babylon or, more likely, writing some time after the year 70 CE.

The Epistle of Jude matches other early second-century literature and self-identifies as from the post-apostolic era, saying to its readers that they “must remember the predictions of the apostles of our Lord Jesus Christ” and how "they [the apostles] told you there should be mockers in the last time" (Jude 17-18).

Scholars have traditionally assigned to Second Peter a date from 124 to 150 CE. It clearly adopts ideas from the second-century Epistle of Jude.

The Revelation of John was once to the apostle John simply because it is signed by a person called John, but several Church Fathers expressed doubt about its authenticity. Modern scholars tend to call its author 'John of Patmos', to distinguish him from the apostle. The book is generally assigned to the 90s of the first century, but this is more because of references to persecution, and the 90s are now called into question as a time of widespread persecution of Christians.