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SUMMARY Medicago truncatulais a model legume for fundamental research on legume biology and symbiotic nitrogen fixation.Tnt1, a retrotransposon from tobacco, was used to generate insertion mutants inM. truncatulaR108. Approximately 21 000 insertion lines have been generated and publicly available.Tnt1retro‐transposition event occurs during somatic embryogenesis (SE), a pivotal process that triggers massive methylation changes. We studied the SE ofM. truncatulaR108 using leaf explants and explored the dynamic shifts in the methylation landscape from leaf explants to callus formation and finally embryogenesis. Higher cytosine methylation in all three contexts of CG, CHG, and CHH patterns was observed during SE compared to the controls. Higher methylation patterns were observed in assumed promoter regions (~2‐kb upstream regions of transcription start site) of the genes, while lowest was recorded in the untranslated regions. Differentially methylated promoter region analysis showed a higher CHH methylation in embryogenesis tissue samples when compared to CG and CHG methylation. Strong correlation (89.71%) was identified between the differentially methylated regions (DMRs) and the site ofTnt1insertions inM. truncatulaR108 and stronger hypermethylation of genes correlated with higher number ofTnt1insertions in all contexts of CG, CHG, and CHH methylation. Gene ontology enrichment and KEGG pathway enrichment analysis identified genes and pathways enriched in the signal peptide processing, ATP hydrolysis, RNA polymerase activity, transport, secondary metabolites, and nitrogen metabolism pathways. Combined gene expression analysis and methylation profiling showed an inverse relationship between methylation in the DMRs (regions spanning genes) and the expression of genes. Our results show that a dynamic shift in methylation happens during the SE process in the context of CG, CHH and CHG methylation, and theTnt1retrotransposition correlates with the hyperactive methylation regions.