diff --git a/Parser/tokenizer.c b/Parser/tokenizer.c
index bdaa65b100f376..34413158672a0e 100644
--- a/Parser/tokenizer.c
+++ b/Parser/tokenizer.c
@@ -1889,7 +1889,7 @@ tok_get_normal_mode(struct tok_state *tok, tokenizer_mode* current_tok, struct t
             }
             c = tok_nextc(tok);
         }
-        if (c == '"' || c == '\'') {
+        if ((c == '"' || c == '\'') && !current_tok->f_string_conversion) {
             in_tag_string = 1;
             goto f_string_quote;
         }
@@ -2225,6 +2225,7 @@ tok_get_normal_mode(struct tok_state *tok, tokenizer_mode* current_tok, struct t
         the_current_tok->kind = TOK_FSTRING_MODE;
         the_current_tok->f_string_quote = quote;
         the_current_tok->f_string_quote_size = quote_size;
+        the_current_tok->f_string_conversion = 0;
         the_current_tok->f_string_start = tok->start;
         the_current_tok->f_string_multi_line_start = tok->line_start;
         the_current_tok->f_string_start_offset = -1;
@@ -2368,6 +2369,10 @@ tok_get_normal_mode(struct tok_state *tok, tokenizer_mode* current_tok, struct t
             return MAKE_TOKEN(ENDMARKER);
         }
 
+        if (c != '!' && current_tok->f_string_conversion) {
+            current_tok->f_string_conversion = 0;
+        }
+
         if (c == ':' && cursor == current_tok->curly_bracket_expr_start_depth) {
             current_tok->kind = TOK_FSTRING_MODE;
             p_start = tok->start;
@@ -2471,6 +2476,10 @@ tok_get_normal_mode(struct tok_state *tok, tokenizer_mode* current_tok, struct t
         return MAKE_TOKEN(syntaxerror(tok, "invalid non-printable character U+%s", hex));
     }
 
+    if (INSIDE_FSTRING_EXPR(current_tok) && c == '!') {
+        current_tok->f_string_conversion = 1;
+    }
+
     /* Punctuation character */
     p_start = tok->start;
     p_end = tok->cur;
diff --git a/Parser/tokenizer.h b/Parser/tokenizer.h
index 2b94aecce626c3..f28d9dcbe1d4d1 100644
--- a/Parser/tokenizer.h
+++ b/Parser/tokenizer.h
@@ -52,6 +52,8 @@ typedef struct _tokenizer_mode {
     const char* f_string_start;
     const char* f_string_multi_line_start;
 
+    int f_string_conversion;
+
     Py_ssize_t f_string_start_offset;
     Py_ssize_t f_string_multi_line_start_offset;