diff --git a/deob/src/main/java/dev/openrs2/deob/Deobfuscator.kt b/deob/src/main/java/dev/openrs2/deob/Deobfuscator.kt
index 88392415..6c4a2e6c 100644
--- a/deob/src/main/java/dev/openrs2/deob/Deobfuscator.kt
+++ b/deob/src/main/java/dev/openrs2/deob/Deobfuscator.kt
@@ -23,6 +23,7 @@ import dev.openrs2.deob.transform.FieldOrderTransformer
 import dev.openrs2.deob.transform.FinalTransformer
 import dev.openrs2.deob.transform.InvokeSpecialTransformer
 import dev.openrs2.deob.transform.MethodOrderTransformer
+import dev.openrs2.deob.transform.MonitorTransformer
 import dev.openrs2.deob.transform.OpaquePredicateTransformer
 import dev.openrs2.deob.transform.OriginalNameTransformer
 import dev.openrs2.deob.transform.OriginalPcRestoreTransformer
@@ -154,6 +155,7 @@ class Deobfuscator(private val input: Path, private val output: Path) {
             ResourceTransformer(),
             OpaquePredicateTransformer(),
             ExceptionTracingTransformer(),
+            MonitorTransformer(),
             BitShiftTransformer(),
             CanvasTransformer(),
             FieldOrderTransformer(),
diff --git a/deob/src/main/java/dev/openrs2/deob/transform/MonitorTransformer.kt b/deob/src/main/java/dev/openrs2/deob/transform/MonitorTransformer.kt
new file mode 100644
index 00000000..f137c845
--- /dev/null
+++ b/deob/src/main/java/dev/openrs2/deob/transform/MonitorTransformer.kt
@@ -0,0 +1,115 @@
+package dev.openrs2.deob.transform
+
+import com.github.michaelbull.logging.InlineLogger
+import dev.openrs2.asm.InsnMatcher
+import dev.openrs2.asm.classpath.ClassPath
+import dev.openrs2.asm.classpath.Library
+import dev.openrs2.asm.nextReal
+import dev.openrs2.asm.previousReal
+import dev.openrs2.asm.transform.Transformer
+import org.objectweb.asm.Opcodes
+import org.objectweb.asm.tree.AbstractInsnNode
+import org.objectweb.asm.tree.ClassNode
+import org.objectweb.asm.tree.InsnNode
+import org.objectweb.asm.tree.JumpInsnNode
+import org.objectweb.asm.tree.LabelNode
+import org.objectweb.asm.tree.MethodNode
+
+class MonitorTransformer : Transformer() {
+    private var subroutinesInlined = 0
+    private var tryRangesExtended = 0
+    private var loadsReplaced = 0
+
+    override fun preTransform(classPath: ClassPath) {
+        subroutinesInlined = 0
+        tryRangesExtended = 0
+        loadsReplaced = 0
+    }
+
+    override fun transformCode(classPath: ClassPath, library: Library, clazz: ClassNode, method: MethodNode): Boolean {
+        inlineSubroutines(method)
+        extendTryRanges(method)
+        replaceLoadWithDup(method)
+        return false
+    }
+
+    private fun inlineSubroutines(method: MethodNode) {
+        val subroutines = mutableMapOf<AbstractInsnNode, List<AbstractInsnNode>>()
+        for (match in SUBROUTINE_MATCHER.match(method.instructions)) {
+            subroutines[match[0]] = match
+        }
+
+        for (match in JSR_MATCHER.match(method.instructions)) {
+            val jsr = match[1] as JumpInsnNode
+            val subroutine = subroutines[jsr.label.nextReal] ?: continue
+
+            val ret = subroutine[3] as JumpInsnNode
+            if (ret.label.nextReal != jsr.nextReal) {
+                continue
+            }
+
+            val clonedLabels = emptyMap<LabelNode, LabelNode>()
+            method.instructions.set(match[0], subroutine[1].clone(clonedLabels))
+            method.instructions.set(match[1], subroutine[2].clone(clonedLabels))
+
+            subroutinesInlined++
+        }
+    }
+
+    private fun extendTryRanges(method: MethodNode) {
+        for (tryCatch in method.tryCatchBlocks) {
+            if (tryCatch.type != null) {
+                continue
+            }
+
+            val monitorenter = tryCatch.start.previousReal ?: continue
+            if (monitorenter.opcode != Opcodes.MONITORENTER) {
+                continue
+            }
+
+            // extend the try to cover the ALOAD and MONTITOREXIT instructions
+            val aload = tryCatch.end.nextReal ?: continue
+            if (aload.opcode != Opcodes.ALOAD) {
+                continue
+            }
+
+            val monitorexit = aload.nextReal ?: continue
+            if (monitorexit.opcode != Opcodes.MONITOREXIT) {
+                continue
+            }
+
+            val end = monitorexit.nextReal ?: continue
+
+            val label = LabelNode()
+            method.instructions.insertBefore(end, label)
+            tryCatch.end = label
+
+            tryRangesExtended++
+        }
+    }
+
+    private fun replaceLoadWithDup(method: MethodNode) {
+        for (match in LOAD_MATCHER.match(method.instructions)) {
+            method.instructions.insertBefore(match[0], InsnNode(Opcodes.DUP))
+            method.instructions.remove(match[1])
+
+            loadsReplaced++
+        }
+    }
+
+    override fun postTransform(classPath: ClassPath) {
+        logger.info { "Inlined $subroutinesInlined MONITOREXIT subroutines" }
+        logger.info { "Extended $tryRangesExtended try ranges to cover MONITOREXIT instructions" }
+        logger.info { "Replaced $loadsReplaced ASTORE ALOAD sequences with DUP ASTORE" }
+    }
+
+    companion object {
+        private val logger = InlineLogger()
+
+        // these regexes rely on JSRInlinerAdapter running first
+        private val JSR_MATCHER = InsnMatcher.compile("ACONST_NULL GOTO")
+        private val SUBROUTINE_MATCHER = InsnMatcher.compile("ASTORE ALOAD MONITOREXIT GOTO")
+
+        private val LOAD_MATCHER = InsnMatcher.compile("ASTORE ALOAD MONITORENTER")
+    }
+}