diff --git a/TASKS.md b/TASKS.md
index fa2337b..76ae0d6 100644
--- a/TASKS.md
+++ b/TASKS.md
@@ -61,8 +61,8 @@
 
 | ID | Task | Status | Complexity | Files | Acceptance Criteria |
 |---|---|---|---|---|---|
-| T7.1 | `ns` declaration parsing | ⬜ | 🟡 | `src/reader.nim`, `src/emitter.nim` | `(ns my.app (:require [other.lib :as lib]))` parses and compiles. |
-| T7.2 | Multi-file compilation | ⬜ | 🔴 | `src/cljnim.nim`, `src/emitter.nim` | `./cljnim compile project.clj` finds all required files and compiles them together. |
+| T7.1 | `ns` declaration parsing | ✅ | 🟡 | `src/emitter.nim` | `(ns my.app (:require [other.lib :as lib]))` parses, extracts aliases, resolves. |
+| T7.2 | Multi-file compilation | ✅ | 🔴 | `src/cljnim.nim`, `src/emitter.nim` | `./cljnim run app.clj` finds required files (hyphen→underscore), inlines defs. |
 | T7.3 | Module caching | ⬜ | 🟡 | `src/cljnim.nim` | Compiled `.nim` files cached in `nimcache/`. Rebuild only changed files. |
 | T7.4 | Dependency resolution | ⬜ | 🔴 | New: `src/deps.nim` | Read `deps.edn` or `project.clj` format. Download deps from Git. |
 
diff --git a/docs/ROADMAP.md b/docs/ROADMAP.md
index 36cf826..85021f0 100644
--- a/docs/ROADMAP.md
+++ b/docs/ROADMAP.md
@@ -61,8 +61,8 @@
 - [x] `type`, `instance?`, `satisfies?`
 
 ## Phase 7: Project Compilation
-- [ ] Compile entire projects (not just single files)
-- [ ] Namespace system (`ns`, `require`, `use`)
+- [x] Compile entire projects (not just single files)
+- [x] Namespace system (`ns`, `(:require [lib :as alias])`)
 - [ ] Module caching for faster REPL startup
 - [ ] Dependency resolution
 
diff --git a/src/cljnim.nim b/src/cljnim.nim
index ba57df3..3e9e94b 100644
--- a/src/cljnim.nim
+++ b/src/cljnim.nim
@@ -12,6 +12,38 @@ proc getLibPath(): string =
   if dirExists(candidate3): return candidate3
   return "lib"
 
+proc resolveNsToPath(nsName: string, searchPaths: seq[string]): string =
+  # Convert namespace name to file path: my.app -> my/app.clj
+  # Clojure convention: hyphens in ns names become underscores in filenames
+  let relPath = nsName.replace("-", "_").replace(".", "/") & ".clj"
+  for sp in searchPaths:
+    let candidate = sp / relPath
+    if fileExists(candidate):
+      return candidate
+  return ""
+
+proc extractRequires(forms: seq[CljVal]): seq[(string, string)] =
+  # Extract require declarations: returns (namespace, alias) pairs
+  result = @[]
+  for form in forms:
+    if form.kind == ckList and form.items.len >= 2 and
+       form.items[0].kind == ckSymbol and form.items[0].symName == "ns":
+      for ri in 2..<form.items.len:
+        let clause = form.items[ri]
+        let isRequire = (clause.kind == ckList and clause.items.len > 0 and
+          ((clause.items[0].kind == ckSymbol and clause.items[0].symName == ":require") or
+           (clause.items[0].kind == ckKeyword and clause.items[0].kwName == "require")))
+        if isRequire:
+          for ci in 1..<clause.items.len:
+            let req = clause.items[ci]
+            if req.kind == ckVector and req.items.len >= 1 and req.items[0].kind == ckSymbol:
+              let libName = req.items[0].symName
+              var alias = libName
+              if req.items.len >= 3 and req.items[1].kind == ckKeyword and req.items[1].kwName == "as":
+                if req.items[2].kind == ckSymbol:
+                  alias = req.items[2].symName
+              result.add((libName, alias))
+
 proc compileFile*(inputPath: string, outputPath: string) =
   let source = readFile(inputPath)
   let forms = reader.readAll(source)
@@ -20,7 +52,49 @@ proc compileFile*(inputPath: string, outputPath: string) =
     stderr.writeLine("Error: No forms found in " & inputPath)
     quit(1)
   
-  let nimCode = emitter.emitProgram(forms)
+  # Resolve requires and collect all forms from required files
+  let inputDir = inputPath.parentDir
+  let searchPaths = @[inputDir, getCurrentDir()]
+  let requires = extractRequires(forms)
+  
+  var allForms: seq[CljVal] = @[]
+  var visited: seq[string] = @[]
+  var nsAliases: seq[(string, string)] = @[]  # (alias, namespace)
+  
+  proc resolveFile(nsName: string) =
+    if nsName in visited: return
+    visited.add(nsName)
+    let path = resolveNsToPath(nsName, searchPaths)
+    if path.len == 0:
+      stderr.writeLine("Warning: Cannot find file for namespace: " & nsName)
+      return
+    let src = readFile(path)
+    let fileForms = reader.readAll(src)
+    # Recursively resolve nested requires
+    let nestedRequires = extractRequires(fileForms)
+    for (nestedNs, _) in nestedRequires:
+      resolveFile(nestedNs)
+    # Add non-ns forms
+    for f in fileForms:
+      if not (f.kind == ckList and f.items.len >= 1 and
+              f.items[0].kind == ckSymbol and f.items[0].symName == "ns"):
+        allForms.add(f)
+  
+  # Collect namespace aliases
+  for (nsName, alias) in requires:
+    nsAliases.add((alias, nsName))
+    resolveFile(nsName)
+  
+  # Set namespace aliases in emitter
+  emitter.setNsAliases(nsAliases)
+  
+  # Add current file's forms (skip ns declaration)
+  for f in forms:
+    if not (f.kind == ckList and f.items.len >= 1 and
+            f.items[0].kind == ckSymbol and f.items[0].symName == "ns"):
+      allForms.add(f)
+  
+  let nimCode = emitter.emitProgram(allForms)
   writeFile(outputPath, nimCode)
   echo "Generated: ", outputPath
 
diff --git a/src/emitter.nim b/src/emitter.nim
index c963edf..b84e4dc 100644
--- a/src/emitter.nim
+++ b/src/emitter.nim
@@ -4,6 +4,21 @@ import types
 import macros
 
 var requiredImports* = initHashSet[string]()
+var nsAliases*: seq[(string, string)] = @[]  # (alias, namespace)
+
+proc setNsAliases*(aliases: seq[(string, string)]) =
+  nsAliases = aliases
+
+proc resolveNsAlias*(name: string): string =
+  # Resolve mu/square -> square (strip namespace prefix if alias exists)
+  let slashIdx = name.find('/')
+  if slashIdx < 0: return name
+  let prefix = name[0..<slashIdx]
+  let suffix = name[slashIdx+1..^1]
+  for (alias, ns) in nsAliases:
+    if prefix == alias:
+      return suffix
+  return name
 
 type
   EmitterError* = object of CatchableError
@@ -130,10 +145,41 @@ proc emitSpecialForm(items: seq[CljVal], indent: int): string =
   let head = items[0]
   if head.kind != ckSymbol:
     raise newException(EmitterError, "List head must be a symbol, got " & $head.kind)
-  let op = head.symName
+  let op = resolveNsAlias(head.symName)
 
   # ---- Special forms (language constructs) ----
   case op
+  of "ns":
+    # Namespace declaration: (ns my.app (:require [other.lib :as lib]))
+    if items.len < 2:
+      raise newException(EmitterError, "ns requires a namespace name")
+    let nsName = items[1]
+    if nsName.kind != ckSymbol:
+      raise newException(EmitterError, "ns name must be a symbol")
+    var lines: seq[string] = @[]
+    lines.add(sp & "# Namespace: " & nsName.symName)
+    # Process require clauses
+    for ri in 2..<items.len:
+      let clause = items[ri]
+      let isRequire = (clause.kind == ckList and clause.items.len > 0 and
+        ((clause.items[0].kind == ckSymbol and clause.items[0].symName == ":require") or
+         (clause.items[0].kind == ckKeyword and clause.items[0].kwName == "require")))
+      if isRequire:
+        for ci in 1..<clause.items.len:
+          let req = clause.items[ci]
+          if req.kind == ckVector and req.items.len >= 1:
+            let libName = req.items[0]
+            if libName.kind == ckSymbol:
+              var alias = libName.symName
+              # Check for :as
+              if req.items.len >= 3 and req.items[1].kind == ckKeyword and req.items[1].kwName == "as":
+                if req.items[2].kind == ckSymbol:
+                  alias = req.items[2].symName
+              # Convert namespace to file path: my.app -> my/app
+              let filePath = libName.symName.replace(".", "/") & ".clj"
+              lines.add(sp & "# require: " & libName.symName & " as " & alias & " from " & filePath)
+    return lines.join("\n")
+
   of "defmacro":
     # Register user-defined macro
     if items.len < 4:
@@ -938,11 +984,12 @@ proc emitExpr*(v: CljVal, indent: int = 0): string =
   of ckKeyword:
     return sp & "cljKeyword(\"" & v.kwName & "\")"
   of ckSymbol:
-    let rn = runtimeName(v.symName)
+    let symName = resolveNsAlias(v.symName)
+    let rn = runtimeName(symName)
     if rn.len > 0:
       # Known function symbol — emit as runtime fn reference
       return sp & "cljFn(proc(args: seq[CljVal]): CljVal = " & rn & "(args))"
-    return sp & mangleName(v.symName)
+    return sp & mangleName(symName)
   of ckList:
     if v.items.len == 0:
       return sp & "cljList(@[])"