E. 1999 Eternal is the second studio album by American hip hop group Bone Thugs-n-Harmony, released July 25, 1995, on Ruthless Records.

Following up on the surprise success of their breakthrough single "Thuggish Ruggish Bone", it became a popular album and received positive reviews from music critics, earning praise for the group's melodic rapping style.

The album title is a portmanteau of Cleveland's eastside neighborhood centering on East 99th Street and St. Clair Avenue where the group is based and the then-future year 1999.

Cheo H. Coker of the Los Angeles Times wrote that the group "has raised the stakes of the gangsta rap game, not only in terms of pure, gritty excess, but also in rhyme-style, cadence and delivery", concluding: "This is the kind of album that starts out good and gets better with repeated listenings—as the dark, subliminal references clear up.

"[6] Retrospectively, Jason Birchmeier of AllMusic described E. 1999 Eternal as "an impressive debut full-length that dismisses any notion that the group was merely a one-hit wonder", adding that it "maintains a consistent tone, one that's menacing and somber, produced entirely by DJ U-Neek, a Los Angeles-based producer who frames the songs with dark, smoked-out G-funk beats and synth melodies.

In a second thought review in Stylus Magazine, the album was described as "Lyrically speaking, Bone Thugs have much in common with countless mainstream rap acts.

Yet, the focus was largely on song craft and melody—the album frequently strays into gloomy territory, but never loses its sense of tunefulness.