The Nibelungenlied was one of the most popular poems of its age, and is probably the best-known Germanic poem from the Middle Ages. Most literary analysis of the poem began after 1800, and soon Germany embraced the poem as a work of nationalism, often comparing it with Homer's Iliad. Essentially, commentary on the Nibelungenlied falls into three categories: the study of source-texts; socio-historical studies; and literary interpretations.

Much of the critical work on the Nibelungenlied since the eighteenth century has been done in German, but English scholarship has appeared as well. Some twentieth-century scholars have analyzed the sources of the poem, concentrating on the author's blend of historical fact, myth, and legend. Other scholars have done more literary analyses of the work, concentrating on characterization, theme and structure. According to T. M. Anderssons's A Preface to the Nibelungenlied, critical work in Germany on the Nibelungenlied from about 1902 to 1941 focused on the context of the early legends which preceded it, dealing primarily in comparisons between the known version of the Nibelungenlied and earlier versions. This critical approach is in keeping with the German to establish the Nibelungenlied's historical significance as a national epic.

After World War II, focus shifted to a more global European context, including historical studies on French historical works and courtly literature. This focus looked at the possible influences on the Nibelungenlied of works such as the Chanson de Roland (Song of Roland) (written aroung 1100) and other heroic tales. The historical context of medieval Germany was also explored to widen this context. Also, explorations of the "courtly" and "chivalric" elements in the work began to appear.

After about 1950, literary approaches dealing with the structure of the poem itself became popular. Such studies, according to Andersson:

assume that the structure is coherent and meaningful, thus departing from an earlier view that the poet recast an inherited story, making piecemeal modifications without strict regard for the overall plan of the poem and without necessarily imputing a consistent meaning to the whole.

It is also Andersson's argument that the first half of the Nibelungenlied was modelled after the second part, and not vice versa.

In recent years, critical commentary has addressed qustions concerning the internal structure of the poem, its characterization, and coherence of plot. Scholarly discussions include the nature of Kriemhild's character development (from innocent bride to avenging queen), Gunther's perceived weaknesses as a king and suitor, and Hagen's guilt or innocence in the context of his role as Gunther and Brunhild's vassal.

Francis G. Gentry's article in Monatshefte (see Sources for Further Study) defends Hagen's actions in killing Siegfried, claiming that as Gunther's chief vassal, his "one concern is to uphold and preserve the honor and integrity of his lord, regardless of the consequences." Not all readers would agree. Rudiger's difficult choice of whether to fight the Burgundians is also defended by Gentry, who suggests that "by entering the battle he is only doing that which is required of him under law, the defense of his lord." However, Gentry also acknowledges the difficulty of Rudiger's decision, and the impossibility of making it with a clear conscience. Rudiger ultimately chooses his feudal obligation over his moral obligation. As Rudiger says in Chapter 37 of the Nibelungenlied, "Whichever course I leave in order to follow the other, I shall have acted basely and infamously." Nevertheless, the choice must be made.

Gunther's character is problematic as well, and has variously been described as both strong and weak. His acquiescence to Siegfried's superior abilities in winning Brunhild is, according to most scholars, a...