diff --git a/src/OpenGl/OpenGl_Text.cxx b/src/OpenGl/OpenGl_Text.cxx
index 4b95885043..a5e7f37098 100755
--- a/src/OpenGl/OpenGl_Text.cxx
+++ b/src/OpenGl/OpenGl_Text.cxx
@@ -696,7 +696,7 @@ void OpenGl_Text::render (const Handle(OpenGl_PrinterContext)& thePrintCtx,
 
     GLdouble x2, y2, z2;
     const GLdouble h = (GLdouble )myFont->FTFont()->PointSize();
-    gluUnProject (myWinX, myWinY + h - 1.0, myWinZ,
+    gluUnProject (myWinX, myWinY + h, myWinZ,
                   (GLdouble* )THE_IDENTITY_MATRIX, myProjMatrix, myViewport,
                   &x2, &y2, &z2);
 
diff --git a/tests/bugs/vis/bug25121 b/tests/bugs/vis/bug25121
new file mode 100644
index 0000000000..5b660f2005
--- /dev/null
+++ b/tests/bugs/vis/bug25121
@@ -0,0 +1,25 @@
+puts "================"
+puts "OCC25121"
+puts "================"
+puts ""
+#######################################################################################
+# Visualization, OpenGl_Text - correct scaling factor for fixed-size text at 3D point
+#######################################################################################
+
+vinit
+
+box b -5 -5 0 10 10 1
+vdisplay -noupdate b
+vtop
+vfit
+
+vdrawtext "000 3D" 0.0 0.0 0.0 255 255 255 1 1 000 0 16 1 Courier
+vdrawtext "001 3D" 0.0 1.0 0.0 255 255 255 1 1 000 0 16 1 Courier
+vdrawtext "101 3D" 0.0 2.0 0.0 255 255 255 1 1 000 0 16 1 Courier
+vdrawtext "110 3D" 0.0 3.0 0.0 255 255 255 1 1 000 0 16 1 Courier
+voverlaytext "000 2D" 100 200 16 Courier 255 255 255 normal 0 0 255
+voverlaytext "001 2D" 100 250 16 Courier 255 255 255 normal 0 0 255
+voverlaytext "101 2D" 100 300 16 Courier 255 255 255 normal 0 0 255
+voverlaytext "110 2D" 100 350 16 Courier 255 255 255 normal 0 0 255
+
+set only_screen 1