Gilbert v. California, 388 U.S. 263 (1967), was an important decision of the Supreme Court of the United States, which was argued February 15–16, 1967, and decided June 12, 1967.

Petitioner alleges constitutional errors in the admission of testimony of some of the witnesses that they had also identified him at a lineup, which occurred 16 days after his indictment and after appointment of counsel, who was not notified, and in in-court identifications of other witnesses present at that lineup; in the admission of handwriting exemplars taken from him after arrest; and in the admission of a co-defendant's out-of-court statements mentioning petitioner's part in the crimes, which statements were held to have been improperly admitted against the co-defendant on the latter's appeal.

(a) The Fifth Amendment privilege against self-incrimination reaches compulsory communications, but a mere handwriting exemplar, in contrast with the content of what is written, is an identifying physical characteristic outside its protection.

The admission of the in-court identifications of petitioner without first determining that they were not tainted by the illegal lineup procedure but were of independent origin was constitutional error.

(a) Since the record does not permit an informed judgment whether the in-court identifications at the two stages of the trial had an independent source, petitioner is entitled only to a vacation of his conviction, pending proceedings in California courts allowing the State to establish that the in-court identifications had an independent source or that their introduction in evidence was harmless error.