diff --git a/include/xo/tokenizer/tokenizer.hpp b/include/xo/tokenizer/tokenizer.hpp
index 8c1b131a..258d4900 100644
--- a/include/xo/tokenizer/tokenizer.hpp
+++ b/include/xo/tokenizer/tokenizer.hpp
@@ -211,7 +211,11 @@ namespace xo {
                 /* can't be 1char punctuation -- can begin assignment token */
                 return false;
             case '=':
-                return true;
+                /* can't be 1char punctuation -- can begin comparison token '==' */
+                return false;
+            case '!':
+                /* can't be 1char punctuation -- can begin comparison token '!=' */
+                return false;
             case '-':
                 /* can't be punctuation
                  * - can appear inside f64 token: e.g. 1.23e-9.
@@ -246,6 +250,12 @@ namespace xo {
             case ':':
                 /* can begin := */
                 return true;
+            case '=':
+                /* can begin == */
+                return true;
+            case '!':
+                /* can begin != */
+                return true;
             }
 
             return false;
@@ -446,6 +456,30 @@ namespace xo {
                     ++ix;
                 }
                 break;
+            case '=':
+                log && log("singleassign or cmpeq token");
+
+                if (*(ix + 1) == '=') {
+                    tk_type = tokentype::tk_cmpeq;
+                    ++ix;
+                    ++ix;
+                } else {
+                    /* standalone '=' */
+                    tk_type = tokentype::tk_singleassign;
+                    ++ix;
+                }
+                break;
+            case '!':
+                if (*(ix + 1) == '=') {
+                    tk_type = tokentype::tk_cmpne;
+                    ++ix;
+                    ++ix;
+                } else {
+                    /* standlone '!' */
+
+                    // TODO
+                }
+                break;
             case '"':
             {
                 log && log("recognize string-token");
@@ -638,10 +672,6 @@ namespace xo {
                 }
                 break;
             }
-            case '=':
-                tk_type = tokentype::tk_singleassign;
-                ++ix;
-                break;
             default:
                 break;
             }
diff --git a/include/xo/tokenizer/tokentype.hpp b/include/xo/tokenizer/tokentype.hpp
index 81a852fa..92d9bf60 100644
--- a/include/xo/tokenizer/tokentype.hpp
+++ b/include/xo/tokenizer/tokentype.hpp
@@ -126,6 +126,11 @@ namespace xo {
             /** operator @c '/' **/
             tk_slash,
 
+            /** operator @c '==' **/
+            tk_cmpeq,
+            /** operator @c '!=' **/
+            tk_cmpne,
+
             /** keyword @c 'type' **/
             tk_type,
 
diff --git a/src/tokenizer/tokentype.cpp b/src/tokenizer/tokentype.cpp
index c19d023b..745651a7 100644
--- a/src/tokenizer/tokentype.cpp
+++ b/src/tokenizer/tokentype.cpp
@@ -43,6 +43,9 @@ namespace xo {
                 CASE(tk_star);
                 CASE(tk_slash);
 
+                CASE(tk_cmpeq);
+                CASE(tk_cmpne);
+
                 CASE(tk_type);
                 CASE(tk_def);
                 CASE(tk_lambda);