Tawayen Lao na 1826–1828 ƙoƙari ne na Sarki Anouvong na Masarautar Vientiane don kawo ƙarshen mulkin Siam da sake ƙirƙirar tsohuwar masarautar Lan Xang.A cikin watan Janairun 1827 sojojin Lao na masarautun Vientiane da Champasak sun ratsa kudu da yamma ta Khorat Plateau, inda suka yi gaba har zuwa Saraburi, kwanaki uku kacal daga babban birnin Siamese na Bangkok.Siamese sun kai farmaki a arewa da gabas, lamarin da ya tilastawa sojojin Lao ja da baya tare da karbe babban birnin Vientiane.Anouvong ya gaza a cikin duka yunƙurin da ya yi na yin adawa da kutsawa Siamese, da kuma duba ƙarin rarrabuwar kawuna tsakanin Lao.An soke Masarautar Vientiane, an tilasta wa jama'arta komawa Siam, kuma tsoffin yankunanta sun fada ƙarƙashin ikon gwamnatin lardin Siamese kai tsaye.Masarautar Champasak da Lan Na sun fi kusantar su cikin tsarin gudanarwa na Siamese.Masarautar Luang Prabang ta yi rauni amma ta ba da damar cin gashin kai a yankin.A cikin fadadata zuwa cikin jihohin Lao, Siam ya wuce gona da iri.Tawayen ya kasance dalilin kai tsaye na yakin Siamese-Vietnamese a cikin 1830s da 1840s.Hare-haren bayi da tilasta wa jama'a canja wurin da Siam ya yi ya haifar da rarrabuwar kawuna tsakanin yankunan da a ƙarshe za su zama Tailandia da Laos, kuma sun sauƙaƙe "ayyukan wayewa" na Faransawa zuwa yankunan Lao a ƙarshen rabin karni na sha tara.