diff --git a/usr.bin/yacc/main.c b/usr.bin/yacc/main.c
index 79b332a237e7..8b7f36ff027f 100644
--- a/usr.bin/yacc/main.c
+++ b/usr.bin/yacc/main.c
@@ -144,7 +144,7 @@ set_signals()
 
 usage()
 {
-    fprintf(stderr, "usage: %s [-dlrtv] [-b file_prefix] [-p symbol_prefix] filename\n", myname);
+    fprintf(stderr, "usage: %s [-dlrtv] [-b file_prefix] [-o output_file_name] [-p symbol_prefix] filename\n", myname);
     exit(1);
 }
 
@@ -189,6 +189,15 @@ char *argv[];
 	    lflag = 1;
 	    break;
 
+	case 'o':
+	    if (*++s)
+		output_file_name = s;
+	    else if (++i < argc)
+		output_file_name = argv[i];
+	    else
+		usage();
+	    continue;
+
 	case 'p':
 	    if (*++s)
 		symbol_prefix = s;
@@ -316,11 +325,13 @@ create_file_names()
 
     len = strlen(file_prefix);
 
+    if (!output_file_name) {
     output_file_name = MALLOC(len + 7);
     if (output_file_name == 0)
 	no_space();
     strcpy(output_file_name, file_prefix);
     strcpy(output_file_name + len, OUTPUT_SUFFIX);
+    }
 
     if (rflag)
     {
diff --git a/usr.bin/yacc/yacc.1 b/usr.bin/yacc/yacc.1
index 787dc0043fe0..3175a22cd35c 100644
--- a/usr.bin/yacc/yacc.1
+++ b/usr.bin/yacc/yacc.1
@@ -86,6 +86,16 @@ If the \fB-l\fR option is specified,
 will not insert the #line directives.
 Any #line directives specified by the user will be retained.
 .TP
+\fB-o \fIoutput_file_name\fR
+The
+.B -o
+option causes
+.I yacc
+to write the generated code to
+.IR output_file_name
+instead of the default file,
+.IR y.tab.c .
+.TP
 \fB-p \fIsymbol_prefix\fR
 The
 .B -p