diff --git a/esphome/components/lvgl/lv_validation.py b/esphome/components/lvgl/lv_validation.py
index fd840cc417..9af25a4e90 100644
--- a/esphome/components/lvgl/lv_validation.py
+++ b/esphome/components/lvgl/lv_validation.py
@@ -274,10 +274,8 @@ def size_validator(value):
         return ["SIZE_CONTENT", "number of pixels", "percentage"]
     if isinstance(value, str) and value.lower().endswith("px"):
         value = cv.int_(value[:-2])
-    if isinstance(value, str) and not value.endswith("%"):
-        if value.upper() == "SIZE_CONTENT":
-            return "LV_SIZE_CONTENT"
-        raise cv.Invalid("must be 'size_content', a percentage or an integer (pixels)")
+    if isinstance(value, str) and value.upper() == "SIZE_CONTENT":
+        return "LV_SIZE_CONTENT"
     return pixels_or_percent_validator(value)
 
 
diff --git a/tests/components/lvgl/lvgl-package.yaml b/tests/components/lvgl/lvgl-package.yaml
index cef76396c2..7fd824a87b 100644
--- a/tests/components/lvgl/lvgl-package.yaml
+++ b/tests/components/lvgl/lvgl-package.yaml
@@ -422,7 +422,7 @@ lvgl:
             id: lv_image
             src: cat_image
             align: top_left
-            y: 50
+            y: "50"
         - tileview:
             id: tileview_id
             scrollbar_mode: active
@@ -461,7 +461,7 @@ lvgl:
               bg_opa: transp
             knob:
               radius: 1
-              width: 4
+              width: "4"
               height: 10%
               bg_color: 0x000000
             width: 100%