Indonesia umur 6-23 bulan tidak mengkonsumsi makanan pendamping ASI yang memadai dan 37% dari anak-anak balita di Indonesia menderita gizi buruk dalam bentuk stunting. Anak yang mengalami stunting menghadapi hambatan belajar di sekolah, berpenghasilan lebih rendah ketika dewasa dan cenderung mewariskan siklus kemiskinan antar generasi. Pemberian MP-ASI dengan tepat dan benar akan mendukung tumbuh kembang bayi baik kognitif, psiÂkomotorik dan menumbuhkan kebiasaan makan yang baik. Tujuan penlitian ini diketahui pengaruh praktik pemberian makanan pendamping air  susu ibu (MP-ASI) terhadap pertumbuhan berat badan bayi 7 bulan di Posyandu Dahlia Desa Datarajan Kecamatan Ulubelu Kabupaten Tanggamus Tahun 2021.Penelitian ini merupakan penelitian eksperimen (experimental), metode quasi eksperiment dengan desain pretest-posttest with control group. Sampel dalam penelitian ini adalah  bayi 7 bulan di Posyandu Dahlia Desa Datarajan Kecamatan Ulubelu Kabupaten Tanggamus yang memenuhi kriteria inklusi dan eksklusi, sebanyak 30 responden. teknik sampling purposive sampling, penelitian menggunakan analisa univariat dan bivariat t-tes indepdnen.Rata-rata berat badan bayi 7 bulan sebelum diberi praktik pemberian makanan pendamping air  susu ibu (MP-ASI) dengan mean 9,233 pada kelompok intervensi dan mean 8,593 pada kelompok kontrol. Rata-rata berat badan bayi 7 bulan sesudah diberi praktik pemberian makanan pendamping air  susu ibu (MP-ASI) dengan mean 9,740 pada kelompok intervensi dan mean 8,773 pada kelompok kontrol. Hasil uji statistik menggunakan tes-independen didapat nilai p-value 0,008 (α<0,05) yang artinya terdapat pengaruh praktik pemberian makanan pendamping air  susu ibu (MP-ASI) terhadap pertumbuhan berat badan bayi 7 bulan di Posyandu Dahlia Desa Datarajan Kecamatan Ulubelu Kabupaten Tanggamus Tahun 2021. Bagi Posyandu Dahlia Desa Datarajan Kecamatan Ulubelu, diharapkan hasil penelitian ini dapat memberikan wacana baru untuk memberikan kegiatan pengajaran praktik pembuatan MP-ASI. ABSTRACTIndonesians aged 6-23 months do not consume adequate complementary foods and 37% of children under five in Indonesia suffer from malnutrition in the form of stunting. Stunting children face learning barriers in school, earn lower incomes as adults and tend to pass on cycles of poverty between generations. Giving MP-ASI correctly and correctly will support the baby's cognitive, psychomotor and developmental growth and foster good eating habits. The purpose of this study was to determine the effect of the practice of giving complementary feeding to breast milk (MP-ASI) on the weight growth of a 7-month-old baby at the Dahlia Posyandu, Datarajan Village, Ulubelu District, Tanggamus Regency in 2021.This research is an experimental research (experimental), quasi-experimental method with pretest-posttest design with control group. The sample in this study was a 7-month-old baby at the Dahlia Posyandu, Datarajan Village, Ulubelu District, Tanggamus Regency who met the inclusion and exclusion criteria, as many as 30 respondents. purposive sampling technique, research using univariate analysis and bivariate independent t-test.The average weight of infants 7 months before being given complementary feeding practices with breast milk (MP-ASI) with a mean of 9,233 in the intervention group and a mean of 8,593 in the control group. The average weight of infants 7 months after being given complementary feeding practices (MP-ASI) with a mean of 9,740 in the intervention group and a mean of 8,773 in the control group. The results of statistical tests using independent tests obtained a p-value of 0.008 (α<0.05), which means that there is an effect of the practice of giving complementary foods to breast milk (MP-ASI) on the weight growth of 7-month babies at the Dahlia Posyandu, Datarajan Village, Ulubelu District. Tanggamus District in 2021. For Posyandu Dahlia, Datarajan Village, Ulubelu District, it is hoped that the results of this study can provide a new discourse to provide teaching activities for the practice of making MP-ASI.