diff --git a/CHANGES.md b/CHANGES.md
index 1f5817824..4c35ec270 100644
--- a/CHANGES.md
+++ b/CHANGES.md
@@ -37,6 +37,10 @@ OSL Language and oslc compiler:
 * A shader input parameter marked with metadata `[[ int allowconnect = 0 ]]`
   will disallow runtime connections via `ConnectShaders()`, resulting in an
   error. #857 (1.10.0)
+* oslc command-line argument `-Werror` will treat all warnings as hard
+  errors (failed compilation). (1.10.0)
+* `#pragma nowarn` will suppress any warnings arising from code on the
+  immediately following line of that source file. (1.10.0)
 
 OSL Standard library:
 
diff --git a/CMakeLists.txt b/CMakeLists.txt
index 5555b42df..e1c6402c2 100644
--- a/CMakeLists.txt
+++ b/CMakeLists.txt
@@ -283,6 +283,7 @@ TESTSUITE ( aastep allowconnect-err and-or-not-synonyms arithmetic
             oslinfo-metadata oslinfo-noparams
             osl-imageio
             paramval-floatpromotion
+            pragma-nowarn
             printf-whole-array
             raytype raytype-specialized reparam
             render-background render-bumptest
diff --git a/src/liboslcomp/oslcomp_pvt.h b/src/liboslcomp/oslcomp_pvt.h
index 0b3e73105..acff5a4b7 100644
--- a/src/liboslcomp/oslcomp_pvt.h
+++ b/src/liboslcomp/oslcomp_pvt.h
@@ -100,7 +100,7 @@ class OSLCompilerImpl {
 
     /// Error reporting
     template<typename... Args>
-    void error (string_view filename, int line,
+    void error (ustring filename, int line,
                 string_view format, const Args&... args) const
     {
         ASSERT (format.size());
@@ -116,10 +116,12 @@ class OSLCompilerImpl {
 
     /// Warning reporting
     template<typename... Args>
-    void warning (string_view filename, int line,
+    void warning (ustring filename, int line,
                   string_view format, const Args&... args) const
     {
         ASSERT (format.size());
+        if (nowarn(filename, line))
+            return;    // skip if the filename/line is on the nowarn list
         std::string msg = OIIO::Strutil::format (format, args...);
         if (msg.size() && msg.back() == '\n')  // trim extra newline
             msg.pop_back();
@@ -135,7 +137,7 @@ class OSLCompilerImpl {
 
     /// Info reporting
     template<typename... Args>
-    void info (string_view filename, int line,
+    void info (ustring filename, int line,
                   string_view format, const Args&... args) const
     {
         ASSERT (format.size());
@@ -150,7 +152,7 @@ class OSLCompilerImpl {
 
     /// message reporting
     template<typename... Args>
-    void message (string_view filename, int line,
+    void message (ustring filename, int line,
                   string_view format, const Args&... args) const
     {
         ASSERT (format.size());
@@ -379,6 +381,16 @@ class OSLCompilerImpl {
         m_func_decls.emplace_back (f);
     }
 
+    // Add a pragma nowarn for the following line
+    void pragma_nowarn () {
+        m_nowarn_lines.insert ({filename(), lineno()+1});
+    }
+
+    // Is the line amont
+    bool nowarn (ustring filename, int line) const {
+        return m_nowarn_lines.find({filename, line}) != m_nowarn_lines.end();
+    }
+
 private:
     void initialize_globals ();
     void initialize_builtin_funcs ();
@@ -477,6 +489,7 @@ class OSLCompilerImpl {
     Symbol *m_derivsym;       ///< Pseudo-symbol to track deriv dependencies
     int m_main_method_start;  ///< Instruction where 'main' starts
     bool m_declaring_shader_formals; ///< Are we declaring shader formals?
+    std::set<std::pair<ustring,int>> m_nowarn_lines;  ///< Lines for 'nowarn'
 };
 
 
diff --git a/src/liboslcomp/osllex.l b/src/liboslcomp/osllex.l
index 5f4ab1eaf..df93dfaad 100644
--- a/src/liboslcomp/osllex.l
+++ b/src/liboslcomp/osllex.l
@@ -306,8 +306,18 @@ preprocess (const char *yytext)
         p++;
     if (! strncmp (p, "pragma", 6)) {
         // pragma
-        oslcompiler->error (oslcompiler->filename(), oslcompiler->lineno(),
-                            "Unknown pragma '%s'", p);
+        OIIO::string_view line (p+6);
+        string_view pragmatype = OIIO::Strutil::parse_word (line);
+        if (OIIO::Strutil::iequals (pragmatype, "osl")) {
+            string_view pragmaname = OIIO::Strutil::parse_word (line);
+            if (pragmaname == "nowarn") {
+                oslcompiler->pragma_nowarn ();
+            } else {
+                oslcompiler->warning (oslcompiler->filename(), oslcompiler->lineno(),
+                                      "Unknown pragma '%s'", pragmaname);
+            }
+        }
+        // N.B. Pragmas that don't start with "osl" are ignored
         oslcompiler->incr_lineno();  // the pragma ends with an EOLN
     } else {  /* probably the line number and filename */
         if (! strncmp (p, "line", 4))
diff --git a/testsuite/pragma-nowarn/ref/out.txt b/testsuite/pragma-nowarn/ref/out.txt
new file mode 100644
index 000000000..fbc6d98a9
--- /dev/null
+++ b/testsuite/pragma-nowarn/ref/out.txt
@@ -0,0 +1,2 @@
+Compiled test.osl -> test.oso
+
diff --git a/testsuite/pragma-nowarn/run.py b/testsuite/pragma-nowarn/run.py
new file mode 100755
index 000000000..cf6a7c29a
--- /dev/null
+++ b/testsuite/pragma-nowarn/run.py
@@ -0,0 +1,11 @@
+#!/usr/bin/env python
+
+# This shader would ordinarily issue a warning.
+# With -Werror, it should be upgraded to an error.
+oslcargs = "-Werror"
+
+# BUT... the shader carefully uses #pragma nowarn to disable the warning.
+# Which should cause the test to pass.
+
+command = testshade("test")
+
diff --git a/testsuite/pragma-nowarn/test.osl b/testsuite/pragma-nowarn/test.osl
new file mode 100644
index 000000000..f80811306
--- /dev/null
+++ b/testsuite/pragma-nowarn/test.osl
@@ -0,0 +1,10 @@
+// Engineer an ambiguous case that should be a warning
+
+normal func () { return 1; }
+vector func () { return 2; }
+
+shader test ()
+{
+    #pragma osl nowarn
+    point p = func();
+}