Oblivion features the voices of Patrick Stewart, Lynda Carter, Sean Bean, Terence Stamp, with celebrity acquisition and voice production being handled by Blindlight.[37][38][39] The voice acting received mixed reviews in the gaming press. While many publications praised it as excellent,[40][41] others found fault with its repetitiveness.[42][43][44] The issue has been blamed on the small number of voice actors and the blandness of the dialogue itself.[45] Lead designer Ken Rolston found the plan to fully voice the game "less flexible, less apt for user projection of his own tone, more constrained for branching, and more trouble for production and disk real estate" than Morrowind's partially recorded dialogue. Rolston tempered his criticism with the suggestion that voice acting "can be a powerful expressive tool" and can contribute significantly to the charm and ambiance of the game. He stated, "I prefer Morrowind's partially recorded dialogue, for many reasons. But I'm told that fully-voiced dialogue is what the kids want."[46]

Oblivion's score was composed by series mainstay Jeremy Soule, a video game composer whose past scores had earned him a British Academy of Film and Television Arts (BAFTA) award in the "Game Music Category" and two nominations for an Academy of Interactive Arts & Sciences (AIAS) award for "Original Music Composition".[47][48] The official soundtrack to Oblivion, featuring 26 tracks spanning 58 minutes, was released in March 2006, via Soule's digital distributor DirectSong.[49][50] Soule had worked with Bethesda and Todd Howard during the creation of Morrowind, and, in a press release announcing his return for Oblivion, Soule repeated the words he had said during Morrowind's press release: "The stunning, epic quality of The Elder Scrolls series is particularly compatible with the grand, orchestral style of music I enjoy composing the most."[47][48] As in his compositions for Morrowind, Soule chose to create a soft and minimalist score so as not to wear out users' ears.[51] Soule stated that while composing the music, he did not imagine any specific characters or events; rather, he wanted it "to comment on the human condition and the beauty of life." In a 2006 interview, he related that this desire came as a result of a car accident that occurred during his composition of the score. He said, "I ended up rolling in my car several times on an interstate while flying headlong into oncoming traffic ... I felt no fear ... I simply just acknowledged to myself that I've had a good life and I would soon have to say goodbye to all of it in a matter of seconds." Soule sustained only minor injuries, but commented that his feeling during the crash—"that life is indeed precious"—remained with him throughout the rest of the composition.[52]