Continuity mistake: During the trial at the end, Jessup struggles with the MPs to get to Danny Kaffee. After the struggle, his tie is all out of place. In the following close-up shots, it's re-aligned, before becoming completely askew as Jessup goes to retrieve his hat.
Deliberate mistake: The extras used in the scene when Danny gets assigned the case appear again as members of the Jury. If Danny's fellow officers were called as Jury members for a trial all would have to declare an interest and be ineligible to hear the case.
Factual error: The crime occurs on Friday, September 6 and the next week, as Kaffee and Weinberg are walking to Weinberg's house and discussing leaving for Cuba the next morning, the ground is covered with leaves and the trees are in full fall color. This doesn't occur in the second (or even the third week) of September in the Washington, D.C./Virginia area. This scene was shot much later, toward the end of October or early November, but it's supposedly well before trial, which is held in early October.
Revealing mistake: In one scene, Tom Cruise is walking along the sidewalk with Kevin Pollak (who is pushing a pram). The camera, which obviously is moving backwards on a dolly, is in front of them. As the men walk past some bushes, watch the branch on the right-hand side. As it comes into view, we see it spring back and shake for a bit. Evidently, the camera dolly snagged it on the way past.
Continuity mistake: In one scene when Sam and Jo are leaving Danny's apartment, there is a wide shot showing Daniel opening the door, then there is a close up of Daniel and Sam, and Sam opens the door again.
Continuity mistake: When Kaffee drives up to the newsstand at night and buys his magazine and chats with the news vendor, his tie knot is undone down to the second button on his shirt. When he returns to his car and is startled by Markinson in the back seat, his tie is undone only a bit past the first button, much higher than the previous shot. This is largely due, Director Rob Reiner explains, to the fact that part of the scene was shot in D.C. and part of the scene was shot in L.A.
Continuity mistake: When Joanne comes to ask Danny why he has not yet seen his clients, he is just about to swing the bat, and begins to as the shot switches to her face. However, in the very next shot he's standing with the bat, waiting to swing again. The time between the two shots would not have provided adequate time for him to swing and then be waiting for another throw.
Continuity mistake: When Jack Ross (Kevin Bacon) calls his first witness to the stand, he steps over to the podium between himself and the defense counsel, but in the wide shot showing the witness walking across the courtroom, he is back at his table. Then in the following close-up he is once again at the podium.
Continuity mistake: In the scene where Jo is telling Danny that she sent one of the prisoners some comic books (towards the beginning of the movie)he steps inside his car and the back window is halfway down. As he drives away it is completely up and as he pulls into the next scene, it is still up, while his driver side window remains down the whole time.
Continuity mistake: Part of Jack's opening statement has him walking towards the jurors with his left arm bent shot from behind the jurors. The next shot is from behind Jack, looking at the jury and his left arm is by his side.
Continuity mistake: Near the end when Jack Nicholson is on the witness stand you can see his collar is wet from sweat, then after he gets up it is dry, then wet again...
Continuity mistake: Just before Danny sits down after questioning Mr. R.C. McGuire, look at his shadows on his jacket. As Jack gets up, notice the sun shadow on his jacket, it's at an angle, but Danny didn't have one.
Continuity mistake: During Danny's drunken yelling scene he swoops a table ALMOST clear of its papers, meaning there are still a few papers messily left on the table. However, a few shots later, those papers are mysteriously missing.
Continuity mistake: During Danny's examination of Lt. Kendrick (Kiefer Sutherland), on the witness stand, he leans up against his courtroom table, shot from the back, in front of the microphone which is straight on, on the table. The next shot, from the front, shows the mic to the left of him and on an angle.
Factual error: In the opening scene, during the overhead shots of the Marine band, the band members are out of step with the music. In military marching, the left foot ALWAYS falls on the downbeat of the music. In all other shots, the music is properly synchronised.
Revealing mistake: In the scene where Tom Cruise is yelling at/questioning Dawson at the jail in the witness room, immediately after Cruise gets up in Dawson's face and says, "I'm the only friend you've got," Cruise is supposed to simply turn and walk away. But you can see from the angle behind Dawson that Cruise' first step is a step down, indicating that he was on a pedestal of some sort to bring their heights closer together.
Continuity mistake: When Danny asks for his bat and Jo (Demi Moore)says she put it in the closet, her elbows are on the table with her hands clasped. She then breaks them and puts the right one on the table. The next shot shows her and Danny and her elbows are on the table again with her hand clasped.
Factual error: During the performance of the Marine Silent Drill Platoon at the very beginning of the movie, they are performing with Springfield 1903 Rifles, whereas the Marines perform with M1 Garands. The reason is that the Texas A&M Fish drill team was being used in the Marines' stead.