diff --git a/ChangeLog.adoc b/ChangeLog.adoc
index af0874183..789f8d2da 100644
--- a/ChangeLog.adoc
+++ b/ChangeLog.adoc
@@ -13,6 +13,10 @@ For a list of important changes that require manual actions, please look at rele
 [[v4.3.0]]
 == Version 4.3.0 (under dev)
 
+New features::
+
+  * core: allow case insensitive search of partial buffer name with `(?i)name` in command `/buffer`
+
 Bug fixes::
 
   * irc: fix random date displayed when a received message contains tags but no "time" (issue #2064)
diff --git a/src/gui/gui-buffer.c b/src/gui/gui-buffer.c
index dfdb46f63..3da3088b5 100644
--- a/src/gui/gui-buffer.c
+++ b/src/gui/gui-buffer.c
@@ -2785,6 +2785,9 @@ gui_buffer_search_main ()
 
 /*
  * Searches for a buffer by full name (example: "irc.libera.#weechat").
+ *
+ * If full_name starts with "(?i)", the search starts after this string
+ * and the search is case insensitive.
  */
 
 struct t_gui_buffer *
@@ -2793,6 +2796,9 @@ gui_buffer_search_by_full_name (const char *full_name)
     struct t_gui_buffer *ptr_buffer;
     int case_sensitive;
 
+    if (!full_name)
+        return NULL;
+
     case_sensitive = 1;
     if (strncmp (full_name, "(?i)", 4) == 0)
     {
@@ -2825,7 +2831,7 @@ struct t_gui_buffer *
 gui_buffer_search_by_name (const char *plugin, const char *name)
 {
     struct t_gui_buffer *ptr_buffer;
-    int plugin_match, case_sensitive;
+    int plugin_match, plugin_case_sensitive, name_case_sensitive;
 
     if (!name || !name[0])
         return gui_current_window->buffer;
@@ -2833,13 +2839,23 @@ gui_buffer_search_by_name (const char *plugin, const char *name)
     if (plugin && (strcmp (plugin, "==") == 0))
         return gui_buffer_search_by_full_name (name);
 
-    case_sensitive = 1;
+    plugin_case_sensitive = 1;
+    name_case_sensitive = 1;
+
+    if (plugin && (strncmp (plugin, "(?i)", 4) == 0))
+    {
+        plugin_case_sensitive = 0;
+        plugin += 4;
+    }
     if (strncmp (name, "(?i)", 4) == 0)
     {
-        case_sensitive = 0;
+        name_case_sensitive = 0;
         name += 4;
     }
 
+    if (!name[0])
+        return gui_current_window->buffer;
+
     for (ptr_buffer = gui_buffers; ptr_buffer;
          ptr_buffer = ptr_buffer->next_buffer)
     {
@@ -2848,14 +2864,19 @@ gui_buffer_search_by_name (const char *plugin, const char *name)
             plugin_match = 1;
             if (plugin && plugin[0])
             {
-                if (strcmp (plugin, gui_buffer_get_plugin_name (ptr_buffer)) != 0)
+                if ((plugin_case_sensitive
+                     && (strcmp (plugin, gui_buffer_get_plugin_name (ptr_buffer)) != 0))
+                    || (!plugin_case_sensitive
+                        && (string_strcasecmp (plugin, gui_buffer_get_plugin_name (ptr_buffer)) != 0)))
+                {
                     plugin_match = 0;
+                }
             }
             if (plugin_match
-                && ((case_sensitive
-                     && strcmp (ptr_buffer->name, name) == 0)
-                    || (!case_sensitive
-                        && string_strcasecmp (ptr_buffer->name, name) == 0)))
+                && ((name_case_sensitive
+                     && (strcmp (ptr_buffer->name, name) == 0))
+                    || (!name_case_sensitive
+                        && (string_strcasecmp (ptr_buffer->name, name) == 0))))
             {
                 return ptr_buffer;
             }
@@ -2868,18 +2889,38 @@ gui_buffer_search_by_name (const char *plugin, const char *name)
 
 /*
  * Searches for a buffer by plugin and partial name.
+ *
+ * If plugin or name starts with "(?i)", the search starts after this string
+ * and the search is case insensitive.
  */
 
 struct t_gui_buffer *
 gui_buffer_search_by_partial_name (const char *plugin, const char *name)
 {
     struct t_gui_buffer *ptr_start_buffer, *ptr_buffer, *buffer_partial_match[3];
-    int plugin_match, length_name;
+    int plugin_case_sensitive, name_case_sensitive, plugin_match, length_name;
     const char *pos;
 
     if (!name || !name[0])
         return gui_current_window->buffer;
 
+    plugin_case_sensitive = 1;
+    name_case_sensitive = 1;
+
+    if (plugin && (strncmp (plugin, "(?i)", 4) == 0))
+    {
+        plugin_case_sensitive = 0;
+        plugin += 4;
+    }
+    if (strncmp (name, "(?i)", 4) == 0)
+    {
+        name_case_sensitive = 0;
+        name += 4;
+    }
+
+    if (!name[0])
+        return gui_current_window->buffer;
+
     /* 0: matches beginning of buffer name, 1: in the middle, 2: the end */
     buffer_partial_match[0] = NULL;
     buffer_partial_match[1] = NULL;
@@ -2899,12 +2940,20 @@ gui_buffer_search_by_partial_name (const char *plugin, const char *name)
             plugin_match = 1;
             if (plugin && plugin[0])
             {
-                if (strcmp (plugin, gui_buffer_get_plugin_name (ptr_buffer)) != 0)
+                if ((plugin_case_sensitive
+                     && (strcmp (plugin, gui_buffer_get_plugin_name (ptr_buffer)) != 0))
+                    || (!plugin_case_sensitive
+                        && (string_strcasecmp (plugin, gui_buffer_get_plugin_name (ptr_buffer)) != 0)))
+                {
                     plugin_match = 0;
+                }
             }
             if (plugin_match)
             {
-                pos = strstr (ptr_buffer->name, name);
+                if (name_case_sensitive)
+                    pos = strstr (ptr_buffer->name, name);
+                else
+                    pos = string_strcasestr (ptr_buffer->name, name);
                 if (pos)
                 {
                     if (pos == ptr_buffer->name)
@@ -2914,7 +2963,7 @@ gui_buffer_search_by_partial_name (const char *plugin, const char *name)
                             /* matches full name, return it immediately */
                             return ptr_buffer;
                         }
-                        /* matches beginning of name */
+                        /* matches beginning of buffer name */
                         if (!buffer_partial_match[0])
                             buffer_partial_match[0] = ptr_buffer;
                     }
diff --git a/tests/unit/gui/test-gui-buffer.cpp b/tests/unit/gui/test-gui-buffer.cpp
index f8a6dcf3c..66a219c66 100644
--- a/tests/unit/gui/test-gui-buffer.cpp
+++ b/tests/unit/gui/test-gui-buffer.cpp
@@ -1256,7 +1256,16 @@ TEST(GuiBuffer, AddValueNumDisplayed)
 
 TEST(GuiBuffer, IsMain)
 {
-    /* TODO: write tests */
+    LONGS_EQUAL(0, gui_buffer_is_main ("", ""));
+    LONGS_EQUAL(0, gui_buffer_is_main (NULL, NULL));
+    LONGS_EQUAL(0, gui_buffer_is_main ("core", NULL));
+    LONGS_EQUAL(0, gui_buffer_is_main ("core", ""));
+    LONGS_EQUAL(0, gui_buffer_is_main (NULL, "weechat"));
+    LONGS_EQUAL(0, gui_buffer_is_main ("", "weechat"));
+    LONGS_EQUAL(0, gui_buffer_is_main ("test", "weechat"));
+    LONGS_EQUAL(0, gui_buffer_is_main ("core", "test"));
+
+    LONGS_EQUAL(1, gui_buffer_is_main ("core", "weechat"));
 }
 
 /*
@@ -1266,7 +1275,24 @@ TEST(GuiBuffer, IsMain)
 
 TEST(GuiBuffer, SearchMain)
 {
-    /* TODO: write tests */
+    struct t_gui_buffer *buffer;
+
+    POINTERS_EQUAL(gui_buffers, gui_buffer_search_main ());
+
+    buffer = gui_buffer_new (NULL, TEST_BUFFER_NAME,
+                             NULL, NULL, NULL,
+                             NULL, NULL, NULL);
+    CHECK(buffer);
+
+    POINTERS_EQUAL(gui_buffers, gui_buffer_search_main ());
+
+    gui_buffer_move_to_number (gui_buffers, 2);
+    POINTERS_EQUAL(gui_buffers->next_buffer, gui_buffer_search_main ());
+
+    gui_buffer_move_to_number (gui_buffers, 2);
+    POINTERS_EQUAL(gui_buffers, gui_buffer_search_main ());
+
+    gui_buffer_close (buffer);
 }
 
 /*
@@ -1276,7 +1302,28 @@ TEST(GuiBuffer, SearchMain)
 
 TEST(GuiBuffer, SearchByFullName)
 {
-    /* TODO: write tests */
+    struct t_gui_buffer *buffer;
+
+    buffer = gui_buffer_new (NULL, TEST_BUFFER_NAME,
+                             NULL, NULL, NULL,
+                             NULL, NULL, NULL);
+    CHECK(buffer);
+
+    POINTERS_EQUAL(NULL, gui_buffer_search_by_full_name (NULL));
+    POINTERS_EQUAL(NULL, gui_buffer_search_by_full_name (""));
+    POINTERS_EQUAL(NULL, gui_buffer_search_by_full_name ("xxx"));
+    POINTERS_EQUAL(NULL, gui_buffer_search_by_full_name ("weechat"));
+
+    POINTERS_EQUAL(gui_buffers, gui_buffer_search_by_full_name ("core.weechat"));
+    POINTERS_EQUAL(buffer, gui_buffer_search_by_full_name ("core." TEST_BUFFER_NAME));
+
+    POINTERS_EQUAL(NULL, gui_buffer_search_by_full_name ("CORE.weechat"));
+    POINTERS_EQUAL(gui_buffers, gui_buffer_search_by_full_name ("(?i)CORE.weechat"));
+
+    POINTERS_EQUAL(NULL, gui_buffer_search_by_full_name ("CORE." TEST_BUFFER_NAME));
+    POINTERS_EQUAL(buffer, gui_buffer_search_by_full_name ("(?i)CORE." TEST_BUFFER_NAME));
+
+    gui_buffer_close (buffer);
 }
 
 /*
@@ -1286,7 +1333,41 @@ TEST(GuiBuffer, SearchByFullName)
 
 TEST(GuiBuffer, SearchByName)
 {
-    /* TODO: write tests */
+    struct t_gui_buffer *buffer;
+
+    buffer = gui_buffer_new (NULL, TEST_BUFFER_NAME,
+                             NULL, NULL, NULL,
+                             NULL, NULL, NULL);
+    CHECK(buffer);
+
+    POINTERS_EQUAL(gui_buffers, gui_buffer_search_by_name (NULL, NULL));
+    POINTERS_EQUAL(gui_buffers, gui_buffer_search_by_name (NULL, ""));
+    POINTERS_EQUAL(gui_buffers, gui_buffer_search_by_name ("", NULL));
+    POINTERS_EQUAL(gui_buffers, gui_buffer_search_by_name ("", ""));
+    POINTERS_EQUAL(gui_buffers, gui_buffer_search_by_name ("==", NULL));
+    POINTERS_EQUAL(gui_buffers, gui_buffer_search_by_name ("==", ""));
+    POINTERS_EQUAL(NULL, gui_buffer_search_by_name ("==", "(?i)"));
+
+    POINTERS_EQUAL(NULL, gui_buffer_search_by_name ("==", "xxx"));
+    POINTERS_EQUAL(NULL, gui_buffer_search_by_name ("==", "weechat"));
+    POINTERS_EQUAL(gui_buffers, gui_buffer_search_by_name ("==", "core.weechat"));
+    POINTERS_EQUAL(buffer, gui_buffer_search_by_name ("==", "core." TEST_BUFFER_NAME));
+
+    POINTERS_EQUAL(gui_buffers, gui_buffer_search_by_name ("", ""));
+    POINTERS_EQUAL(gui_buffers, gui_buffer_search_by_name ("", "(?i)"));
+
+    POINTERS_EQUAL(gui_buffers, gui_buffer_search_by_name ("core", "weechat"));
+    POINTERS_EQUAL(buffer, gui_buffer_search_by_name ("core", TEST_BUFFER_NAME));
+
+    POINTERS_EQUAL(NULL, gui_buffer_search_by_name ("CORE", "WEECHAT"));
+    POINTERS_EQUAL(gui_buffers, gui_buffer_search_by_name ("(?i)CORE", "weechat"));
+    POINTERS_EQUAL(gui_buffers, gui_buffer_search_by_name ("core", "(?i)WEECHAT"));
+    POINTERS_EQUAL(gui_buffers, gui_buffer_search_by_name ("(?i)CORE", "(?i)WEECHAT"));
+
+    POINTERS_EQUAL(NULL, gui_buffer_search_by_name ("CORE", TEST_BUFFER_NAME));
+    POINTERS_EQUAL(buffer, gui_buffer_search_by_name ("(?i)CORE", TEST_BUFFER_NAME));
+
+    gui_buffer_close (buffer);
 }
 
 /*
@@ -1296,7 +1377,37 @@ TEST(GuiBuffer, SearchByName)
 
 TEST(GuiBuffer, SearchByPartialName)
 {
-    /* TODO: write tests */
+    struct t_gui_buffer *buffer;
+
+    buffer = gui_buffer_new (NULL, TEST_BUFFER_NAME,
+                             NULL, NULL, NULL,
+                             NULL, NULL, NULL);
+    CHECK(buffer);
+
+    POINTERS_EQUAL(gui_buffers, gui_buffer_search_by_partial_name (NULL, NULL));
+    POINTERS_EQUAL(gui_buffers, gui_buffer_search_by_partial_name (NULL, ""));
+    POINTERS_EQUAL(gui_buffers, gui_buffer_search_by_partial_name ("", NULL));
+    POINTERS_EQUAL(gui_buffers, gui_buffer_search_by_partial_name ("", ""));
+    POINTERS_EQUAL(gui_buffers, gui_buffer_search_by_partial_name ("", "(?i)"));
+
+    POINTERS_EQUAL(gui_buffers, gui_buffer_search_by_partial_name ("core", "weechat"));
+    POINTERS_EQUAL(buffer, gui_buffer_search_by_partial_name ("core", TEST_BUFFER_NAME));
+
+    POINTERS_EQUAL(NULL, gui_buffer_search_by_partial_name ("CORE", "WEECHAT"));
+    POINTERS_EQUAL(gui_buffers, gui_buffer_search_by_partial_name ("(?i)CORE", "weechat"));
+    POINTERS_EQUAL(gui_buffers, gui_buffer_search_by_partial_name ("core", "(?i)WEECHAT"));
+    POINTERS_EQUAL(gui_buffers, gui_buffer_search_by_partial_name ("(?i)CORE", "(?i)WEECHAT"));
+    POINTERS_EQUAL(gui_buffers, gui_buffer_search_by_partial_name ("(?i)CORE", "(?i)WEE"));
+    POINTERS_EQUAL(gui_buffers, gui_buffer_search_by_partial_name ("(?i)CORE", "(?i)CH"));
+    POINTERS_EQUAL(gui_buffers, gui_buffer_search_by_partial_name ("(?i)CORE", "(?i)CHAT"));
+    POINTERS_EQUAL(buffer, gui_buffer_search_by_partial_name ("(?i)CORE", "(?i)S"));
+
+    POINTERS_EQUAL(NULL, gui_buffer_search_by_partial_name ("CORE", TEST_BUFFER_NAME));
+    POINTERS_EQUAL(buffer, gui_buffer_search_by_partial_name ("(?i)CORE", TEST_BUFFER_NAME));
+
+    gui_buffer_close (buffer);
+
+    POINTERS_EQUAL(gui_buffers, gui_buffer_search_by_partial_name ("core", "weechat"));
 }
 
 /*
@@ -1306,7 +1417,21 @@ TEST(GuiBuffer, SearchByPartialName)
 
 TEST(GuiBuffer, SearchByNumber)
 {
-    /* TODO: write tests */
+    struct t_gui_buffer *buffer;
+
+    buffer = gui_buffer_new (NULL, TEST_BUFFER_NAME,
+                             NULL, NULL, NULL,
+                             NULL, NULL, NULL);
+    CHECK(buffer);
+
+    POINTERS_EQUAL(NULL, gui_buffer_search_by_number (-1));
+    POINTERS_EQUAL(NULL, gui_buffer_search_by_number (0));
+    POINTERS_EQUAL(NULL, gui_buffer_search_by_number (3));
+
+    POINTERS_EQUAL(gui_buffers, gui_buffer_search_by_number (1));
+    POINTERS_EQUAL(buffer, gui_buffer_search_by_number (2));
+
+    gui_buffer_close (buffer);
 }
 
 /*
@@ -1316,7 +1441,34 @@ TEST(GuiBuffer, SearchByNumber)
 
 TEST(GuiBuffer, SearchByNumberOrName)
 {
-    /* TODO: write tests */
+    struct t_gui_buffer *buffer;
+
+    buffer = gui_buffer_new (NULL, TEST_BUFFER_NAME,
+                             NULL, NULL, NULL,
+                             NULL, NULL, NULL);
+    CHECK(buffer);
+
+    POINTERS_EQUAL(NULL, gui_buffer_search_by_number_or_name (NULL));
+    POINTERS_EQUAL(NULL, gui_buffer_search_by_number_or_name (""));
+    POINTERS_EQUAL(NULL, gui_buffer_search_by_number_or_name ("xxx"));
+    POINTERS_EQUAL(NULL, gui_buffer_search_by_number_or_name ("-1"));
+    POINTERS_EQUAL(NULL, gui_buffer_search_by_number_or_name ("0"));
+    POINTERS_EQUAL(NULL, gui_buffer_search_by_number_or_name ("3"));
+
+    POINTERS_EQUAL(gui_buffers, gui_buffer_search_by_number_or_name ("1"));
+    POINTERS_EQUAL(buffer, gui_buffer_search_by_number_or_name ("2"));
+
+    POINTERS_EQUAL(gui_buffers, gui_buffer_search_by_number_or_name ("weechat"));
+    POINTERS_EQUAL(gui_buffers, gui_buffer_search_by_number_or_name ("core.weechat"));
+    POINTERS_EQUAL(NULL, gui_buffer_search_by_number_or_name ("CORE.WEECHAT"));
+    POINTERS_EQUAL(gui_buffers, gui_buffer_search_by_number_or_name ("(?i)CORE.WEECHAT"));
+
+    POINTERS_EQUAL(buffer, gui_buffer_search_by_number_or_name (TEST_BUFFER_NAME));
+    POINTERS_EQUAL(buffer, gui_buffer_search_by_number_or_name ("core." TEST_BUFFER_NAME));
+    POINTERS_EQUAL(NULL, gui_buffer_search_by_number_or_name ("CORE." TEST_BUFFER_NAME));
+    POINTERS_EQUAL(buffer, gui_buffer_search_by_number_or_name ("(?i)CORE." TEST_BUFFER_NAME));
+
+    gui_buffer_close (buffer);
 }
 
 /*