diff --git a/.gitignore b/.gitignore
index 156c7df..2811665 100644
--- a/.gitignore
+++ b/.gitignore
@@ -1,2 +1,4 @@
-build/
 dependencies/
+build.ninja
+.ninja_log
+build/
diff --git a/get-dependencies.sh b/get-dependencies.sh
index 7f0f319..5b025bc 100644
--- a/get-dependencies.sh
+++ b/get-dependencies.sh
@@ -2,13 +2,8 @@
 
 LIMINE_VERSION="9.3.4"
 
-if [ -e dependencies/.got-all ]; then
-  echo already got dependencies.
-  exit
-fi
-
 if [ -e dependencies ]; then
-  echo it looks like we started getting the dependencies, and did not finish. delete the dependencies directory and run this again to try again.
+  echo dependencies directory already exists.
   exit
 fi
 
@@ -21,5 +16,3 @@ curl -L https://github.com/limine-bootloader/limine/archive/refs/tags/v${LIMINE_
 mv limine-${LIMINE_VERSION}-binary limine
 make -C limine
 cd ..
-
-touch dependencies/.got-all
diff --git a/make-build.sh b/make-build.sh
new file mode 100644
index 0000000..4bffb5f
--- /dev/null
+++ b/make-build.sh
@@ -0,0 +1,67 @@
+#!/bin/sh
+
+COMMON_CC_EXTRA_FLAGS="-O3 -Wall -Wextra"
+COMMON_CC_FLAGS="-std=c23 ${COMMON_CC_EXTRA_FLAGS}"
+KERNEL_CC_FLAGS="-I dependencies/limine -I kernel/include -mno-sse -ffreestanding ${COMMON_CC_FLAGS}"
+
+if [ -e build.ninja ]; then
+  echo build.ninja already exists.
+  exit
+fi
+
+set -e
+
+echo "rule nasm" >> build.ninja
+echo "  command = nasm -f elf64 \$in -o \$out" >> build.ninja
+
+echo "rule kernel_cc" >> build.ninja
+echo "  depfile = \$out.d" >> build.ninja
+echo "  command = cc -c -MD -MF \$out.d ${KERNEL_CC_FLAGS} \$in -o \$out" >> build.ninja
+
+echo "rule kernel_ld" >> build.ninja
+echo "  command = ld -T kernel/link.ld \$in -o \$out" >> build.ninja
+
+ALL_KERNEL_OBJECTS=""
+
+for f in kernel/src/*.asm; do
+  f=$(echo $f | sed -e 's/^kernel\/src\///')
+  echo "build build/kernel/$f.o: nasm kernel/src/$f" >> build.ninja
+  ALL_KERNEL_OBJECTS="${ALL_KERNEL_OBJECTS} build/kernel/$f.o"
+done
+
+for f in kernel/src/*.c; do
+  f=$(echo $f | sed -e 's/^kernel\/src\///')
+  echo "build build/kernel/$f.o: kernel_cc kernel/src/$f" >> build.ninja
+  ALL_KERNEL_OBJECTS="${ALL_KERNEL_OBJECTS} build/kernel/$f.o"
+done
+
+echo "build build/kernel/kernel.elf: kernel_ld ${ALL_KERNEL_OBJECTS}" >> build.ninja
+
+echo "rule initfs" >> build.ninja
+echo "  command =" \
+  "rm -rf build/initfs &&" \
+  "mkdir -p build/initfs/resx &&" \
+  "echo Hello! > build/initfs/resx/hello.txt &&" \
+  "cd build/initfs &&" \
+  "tar cf ../initfs.tar *" >> build.ninja
+
+echo "build build/initfs.tar: initfs" >> build.ninja
+
+echo "rule disk" >> build.ninja
+echo "  command =" \
+  "rm -rf build/disk &&" \
+  "cp -r disk build/disk &&" \
+  "cp dependencies/limine/limine-uefi-cd.bin build/disk/limine/ &&" \
+  "cp dependencies/limine/limine-bios-cd.bin build/disk/limine/ &&" \
+  "cp dependencies/limine/limine-bios.sys build/disk/limine/ &&"\
+  "mkdir -p build/disk/EFI/BOOT &&" \
+  "cp dependencies/limine/BOOTX64.EFI build/disk/EFI/BOOT/ &&" \
+  "mkdir build/disk/calcite &&" \
+  "cp build/kernel/kernel.elf build/disk/calcite/ &&" \
+  "cp build/initfs.tar build/disk/calcite/ &&" \
+  "xorriso -as mkisofs -R -r -J -b limine/limine-bios-cd.bin -no-emul-boot -boot-load-size 4 -boot-info-table -hfsplus -apm-block-size 2048 --efi-boot limine/limine-uefi-cd.bin -efi-boot-part --efi-boot-image --protective-msdos-label build/disk -o build/disk.iso &&" \
+  "dependencies/limine/limine bios-install build/disk.iso" >> build.ninja
+
+echo "build build/disk.iso: disk | build/kernel/kernel.elf build/initfs.tar" >> build.ninja
+
+echo "default build/disk.iso" >> build.ninja
diff --git a/makefile b/makefile
deleted file mode 100644
index 2f154f8..0000000
--- a/makefile
+++ /dev/null
@@ -1,57 +0,0 @@
-COMMON_CC_EXTRA_FLAGS = -O3 -Wall -Wextra
-COMMON_CC_FLAGS = -std=c23 ${CC_EXTRA_FLAGS}
-KERNEL_CC_FLAGS = -mno-sse -ffreestanding ${COMMON_CC_FLAGS}
-
-.PHONY: default
-default: build/disk.iso
-
-.PHONY: debug
-debug: build/disk.iso
-	gdb -x qemu.gdb
-
-.PHONY: clean
-clean:
-	rm -rf build
-
-# kernel
-
-KERNEL_SOURCES = entry.c initfs.c paging.asm paging.c
-
-build/kernel/%.asm.o: kernel/src/%.asm
-	@mkdir -p ${@D}
-	nasm -f elf64 $^ -o $@
-
-build/kernel/%.c.o: kernel/src/%.c
-	@mkdir -p ${@D}
-	cc -c ${KERNEL_CC_FLAGS} -I dependencies/limine -I kernel/include $^ -o $@
-
-build/kernel/kernel.elf: ${KERNEL_SOURCES:%=build/kernel/%.o}
-	ld -T kernel/link.ld $^ -o $@
-
-# initfs
-
-build/initfs.tar:
-	rm -rf build/initfs
-	mkdir -p build/initfs/resx
-	echo Hello! > build/initfs/resx/hello.txt
-	cd build/initfs; tar cf ../initfs.tar *
-
-# disk
-
-build/disk.iso: build/kernel/kernel.elf build/initfs.tar
-	rm -rf build/disk
-	cp -r disk build/disk
-	cp dependencies/limine/limine-uefi-cd.bin build/disk/limine/
-	cp dependencies/limine/limine-bios-cd.bin build/disk/limine/
-	cp dependencies/limine/limine-bios.sys build/disk/limine/
-	mkdir -p build/disk/EFI/BOOT
-	cp dependencies/limine/BOOTX64.EFI build/disk/EFI/BOOT/
-	mkdir build/disk/calcite
-	cp build/kernel/kernel.elf build/disk/calcite/
-	cp build/initfs.tar build/disk/calcite/
-	xorriso \
-	  -as mkisofs -R -r -J -b limine/limine-bios-cd.bin -no-emul-boot \
-	  -boot-load-size 4 -boot-info-table -hfsplus -apm-block-size 2048 \
-	  --efi-boot limine/limine-uefi-cd.bin -efi-boot-part --efi-boot-image \
-	  --protective-msdos-label build/disk -o build/disk.iso
-	dependencies/limine/limine bios-install build/disk.iso
diff --git a/readme.txt b/readme.txt
index 2c72af4..7e02cd4 100644
--- a/readme.txt
+++ b/readme.txt
@@ -15,17 +15,21 @@ Calcite requires some software to be installed before it can be built:
  * curl
  * GCC (Any C compiler supporting both C99 and C23 should work.)
  * GNU Binutils (Specifically, "ld" is used to link the kernel.)
- * GNU Make (I don't think I have used any GNU extensions.)
  * GNU tar (Any POSIX tar should be fine.)
  * GNU xorriso
  * NASM
+ * Ninja build system
 
 On Debian, it is sufficient to run this command:
-  apt install binutils curl gcc make nasm tar xorriso
+  apt install binutils curl gcc nasm ninja-build tar xorriso
 
-To build Calcite, first run "sh get-dependencies.sh", then run "make".
-This will build a disk image at "build/disk.iso" that can be booted
-with either BIOS or UEFI.
+To build Calcite, run these commands:
+  sh get-dependencies.sh
+  sh make-build.sh
+  ninja
+
+This will build a disk image at "build/disk.iso" that can be booted with
+either BIOS or UEFI.
 
 === Debugging
 
@@ -36,12 +40,16 @@ Once Calcite has been built, some more software is required to debug it:
 On Debian, it is sufficient to run this command:
   apt install gdb qemu-system-x86
 
-Then, just run "make debug". Calcite will be booted in QEMU, and GDB will be
-attached to it. Use "c" or "continue" in GDB to start execution.
+Then, just run "gdb -x qemu.gdb". Calcite will be booted in QEMU, and GDB will
+be attached to it. Use "c" or "continue" in GDB to start execution.
 
 While debugging, it is useful to disable optimizations and enable debugging
-information. In the makefile, under CC_EXTRA_FLAGS, you can change "-O3" to
-"-Og -ggdb". Then, run "make clean" and then "make" again.
+information. In "make-build.sh", under COMMON_CC_EXTRA_FLAGS, you can change
+"-O3" to "-Og -ggdb". Then, run these commands to rebuild:
+  rm -r build
+  rm build.ninja
+  sh make-build.sh
+  ninja
 
 === License